JP2022161573A - Magnetoelectric conversion element - Google Patents

Abstract

To provide a magnetoelectric conversion element capable of ensuring independence of vibration of each vibrating body.SOLUTION: A magnetoelectric conversion element includes: a substrate in which a plurality of lower spaces with at least part of a fixed part arranged therebetween is formed; and a plurality of vibrating bodies which is provided corresponding to the lower spaces and each of which is supported to be vibratable on the lower space via a support arm part connected to the fixed part, the vibrating bodies having magnetoelectric conversion properties. Each lower space is connected to an upper space, which is an upper space of the vibrating body, via a gap between the corresponding vibrating body and the substrate. The cross sectional area of a first cross section that is parallel to a main surface of the vibrating body in the fixed part and has a first distance from the upper end of the fixed part is narrower than the cross sectional area of a second cross section that is parallel to the main surface of the vibrating body in the fixed part and has a second distance from the upper end of the fixed part, the second distance being longer than the first distance.SELECTED DRAWING: Figure 5

Description

The present invention relates to a magnetoelectric transducer having a plurality of vibrating bodies.

Techniques for constructing a magnetoelectric conversion element by combining a piezoelectric material and a ferromagnetic material have been proposed, and development of various devices using the magnetoelectric conversion element is being studied. For example, as a compact magnetoelectric conversion element having useful characteristics, a device in which a vibrating body having magnetoelectric conversion properties is arranged on a substrate has been proposed.

On the other hand, if it is possible to configure an energy conversion element by combining a plurality of small energy conversion portions, it may be possible to realize a compact energy conversion element with high performance. However, if a plurality of vibrating bodies having magnetoelectric conversion properties are densely arranged on the substrate, the substrate supporting the vibrating bodies vibrates, which causes a problem of degraded magnetoelectric conversion characteristics. In addition, when a plurality of vibrating bodies are arranged close to each other, the vibrations of the vibrating bodies are transmitted to each other, which causes problems such as deterioration in magnetoelectric conversion characteristics and difficulty in control.

Japanese Patent Application Laid-Open No. 2020-169881

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and provides a magnetoelectric conversion element having a plurality of vibrating bodies, in which the independence of vibration of each vibrating body can be ensured.

In order to achieve the above object, the magnetoelectric conversion element according to the present invention comprises:
a substrate having a plurality of lower spaces between which at least part of the fixing part is arranged;
a plurality of vibrating bodies that are provided corresponding to the lower space, are oscillatably supported in the lower space via support arms connected to the fixing portion, and have magnetoelectric conversion properties;
each of the lower spaces is connected to an upper space above the vibrating body through a gap between the corresponding vibrating body and the substrate;
A cross-sectional area of a first cross section that is parallel to the main surface of the vibrating body in the fixing portion and is a first distance from the upper end of the fixing portion is parallel to the main surface of the vibrating body in the fixing portion. It is characterized by being narrower than the cross-sectional area of a second cross section, which is a second distance longer than the first distance from the upper end of the fixing portion.

In the magnetoelectric transducer according to the present invention, a plurality of vibrating bodies can be arranged close to each other by arranging the vibrating bodies so as to correspond to the lower space between which at least part of the fixing portion is arranged. Further, by narrowing the cross-sectional area of the first cross section of the fixing portion, it is possible to arrange the plurality of vibrating bodies closer to each other while ensuring the arrangement and vibration space of the vibrating bodies and the supporting arm portions. Further, by widening the second cross section, the rigidity of the fixed portion is increased to prevent the fixed portion from vibrating, ensuring the independence of the vibration of each vibrating body, and obtaining good magnetoelectric conversion characteristics. can be done.

Further, for example, the primary resonance frequency of the fixing portion may be lower than the resonance frequency at which the vibrator operates.

Such a magnetoelectric conversion element can effectively prevent the vibration of the fixed part that supports the vibrating body by preventing the resonance of the fixed part caused by the operation of the vibrating body. can be obtained.

Further, for example, the fundamental resonance frequency of the vibration mode of the fixed portion displaced in the same direction as the vibration direction of the vibration mode in which the vibrating body operates may be lower than the resonance frequency in which the vibrating body operates.

Such a magnetoelectric conversion element can particularly effectively prevent vibration of the fixed portion that supports the vibrating body by preventing resonance of the fixed portion caused by the operation of the vibrating body, resulting in excellent magnetoelectric conversion. properties can be obtained.

Further, for example, the fixed portion has a transitional change in which the cross-sectional area of the section parallel to the main surface of the vibrator in the fixed portion transitionally narrows as the distance from the upper end of the fixed portion decreases. may have a part.

The fixed part having the transition change part can prevent the cross-sectional area of the fixed part from changing abruptly in the vertical direction, and can effectively increase the rigidity of the fixed part as a whole.

Further, for example, the fixing portion may have a step surface connecting a first side surface of the first portion including the first cross section and a second side surface of the second portion including the second cross section.

By forming a shape having such a stepped surface, the fixing portion having the first cross section and the second cross section can be formed relatively easily by etching or the like. is good.

The vibrator may have a film lamination section including a piezoelectric film and a ferromagnetic film.

A vibrating body having a film lamination portion including a piezoelectric film and a ferromagnetic film is compact and exhibits excellent magnetoelectric conversion properties.

FIG. 1 is a partial plan view of a magnetoelectric transducer according to one embodiment of the present invention. FIG. 2 is an enlarged plan view enlarging the periphery of one vibrator included in the magnetoelectric transducer shown in FIG. FIG. 3 is a cross-sectional view taken along line III--III shown in FIG. FIG. 4 is a cross-sectional view taken along line IV--IV shown in FIG. FIG. 5 is a conceptual diagram schematically showing the shapes of the fixed portion and the vibrator in the magnetoelectric transducer. FIG. 6 is a conceptual diagram schematically showing the shapes of a fixed portion and a vibrating body in the magnetoelectric transducer according to the second embodiment. FIG. 7 is a conceptual diagram schematically showing the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the third embodiment. FIG. 8 is a conceptual diagram schematically showing the shapes of a fixed portion and a vibrating body in a magnetoelectric conversion element according to a fourth embodiment. FIG. 9 is a conceptual diagram schematically showing the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the fifth embodiment. FIG. 10 is a conceptual diagram schematically showing the shapes of the fixed portion and the vibrating body in the magnetoelectric transducer according to the sixth embodiment. FIG. 11 is a conceptual diagram schematically showing the shapes of a fixed portion and a vibrating body in a magnetoelectric transducer according to the seventh embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

First Embodiment FIG. 1 is a partial plan view of a magnetoelectric transducer 30 according to a first embodiment of the present invention. As shown in FIG. 1, the magnetoelectric conversion element 30 is provided with a substrate 40 having a plurality of lower spaces 40b between which fixing portions 41 are arranged, and provided corresponding to each of the lower spaces 40b. and a plurality of vibrating bodies 70 having 1 to 4 and FIG. 5(a), illustration of the cover portion 90 shown in FIG. 5(b) is omitted for convenience of explanation.

As shown in FIG. 1, in the substrate 40, a plurality of lower spaces 40b having substantially rectangular upper openings when viewed from above (positive Z-axis direction) are formed along the X-axis direction and the Y-axis direction. Each lower space 40b is partitioned by the fixing portion 41 in the X-axis direction, and partitioned by the connecting portion 48 in the Y-axis direction. A frame portion 49 (see FIG. 5B) of the substrate 40 constitutes the outer peripheral portion of the substrate 40 .

The vibrating body 70 is arranged so as to block a part of the upper opening of each lower space 40b. FIG. 2 is an enlarged plan view showing one vibrating body 70 shown in FIG. 1 and its peripheral portion, and FIGS. FIG. 4 is a cross-sectional view along IV; 2 to 4 also show the detailed structure of the vibrating body 70, which is not shown in FIG.

As shown in FIGS. 2 and 3, the vibrating body 70 is oscillatably supported above the lower space 40b via a supporting arm portion 80 connected to the fixed portion 41. As shown in FIG. As shown in FIGS. 2 and 4, a gap 94 is formed between the vibrating body 70 and the fixed portion 41 and connecting portion 48 of the substrate 40 . As shown in FIG. 4, each of the lower spaces 40b is arranged above the vibrating body 70 (on the Z-axis positive direction side) via a gap 94 between the vibrating body 70 and the substrate 40 provided corresponding to the lower space 40b. is connected to an upper space 90a which is a space of

As shown in FIG. 1, the magnetoelectric conversion element 30 is an array in which a plurality of vibrating bodies 70 are electrically connected by electrode films (a first extraction electrode film 50a and a second extraction electrode film 50b, which will be described later) and wiring portions 96. constitutes the element. The magnetoelectric conversion element 30 shown in FIG. 1 is a 2D array element in which a plurality of vibrating bodies 70 are arranged in a two-dimensional direction. may be arranged in a one-dimensional direction (for example, the X-axis direction), or a 3D array element in which a plurality of vibrating bodies 70 are arranged three-dimensionally. A magnetic conversion element, which is a 3D array element, can be configured by, for example, stacking a plurality of magnetoelectric conversion elements 30 shown in FIG. 1 in the vertical direction (Z-axis direction).

The vibrating body 70 of the magnetoelectric conversion element 30 includes a piezoelectric film central portion 72, a ferromagnetic film 73, etc., as shown in FIG. have. The magnetoelectric conversion element shown in FIG. 1 can effectively absorb input energy that accompanies fluctuations in an electromagnetic field, perform magnetoelectric conversion, and obtain a high electrical output. Magnetoelectric transducers can also efficiently convert, for example, electrical input energy into output signals such as magnetic field fluctuations.

The magnetoelectric conversion element 30 is connected to a power source and an electric/electronic circuit and mounted on a circuit board or packaged to constitute an electronic device such as an energy conversion device or a magnetic sensor. Application examples of the magnetoelectric conversion element 30 include, for example, a small high-sensitivity magnetic sensor that detects magnetism, a high-sensitivity magnetic antenna, a power transmission unit and a power reception unit of a contactless power supply system in a small device, and the like. Not limited.

1 to 5, the direction connecting the two support arms 80 on both sides of the vibrating body 70 is the X-axis direction, and the space 40b under the substrate 40 and the vibrating body 70 The normal direction of the main surface 70a (see FIG. 5(b)) will be described as the Z-axis direction, and the X-axis direction and the direction perpendicular to the Z-axis direction will be described as the Y-axis direction. However, in the magnetoelectric conversion element 30, the X-axis direction and the Y-axis direction do not have to be aligned horizontally, and the Z-axis direction may be aligned horizontally. You may arrange|position so that it may become diagonal with respect to a horizontal plane.

As shown in FIG. 2, the combined portion of one vibrating body 70 and the lower space 40b in the magnetoelectric conversion element 30 is arranged in an area having a generally rectangular plan view shape as a whole. The vibrating body 70 is formed along a plane including the X-axis and the Y-axis, and has a substantially rectangular shape in plan view.

FIG. 3 is a cross-sectional view taken along line III--III shown in FIG. As shown in FIG. 3, the substrate 40 exists as the lowest layer in the Z-axis direction of the magnetoelectric transducer 30 . The substrate 40 has a lower space 40b in a portion overlapping the vibrating body 70 when viewed in the Z-axis direction. The vibrating body 70 positioned above the Z-axis of the lower space 40 b includes a lower metal film central portion 74 , a piezoelectric film central portion 72 positioned above the lower metal film central portion 74 , and a piezoelectric film central portion 72 positioned above the piezoelectric film central portion 72 . and a ferromagnetic film 73 located at the position of the film stack.

The film lamination portion of the vibrating body 70 is laminated with the piezoelectric film central portion 72 sandwiched between the lower metal film central portion 74 and the ferromagnetic film 73 . Therefore, voltage can be applied to the piezoelectric film central portion 72 via the lower metal film central portion 74 and the ferromagnetic film 73 . Alternatively, the charge generated in the piezoelectric film central portion 72 can be taken out through the lower metal film central portion 74 and the ferromagnetic film 73 .

In the vibrating body 70, the ferromagnetic film 73 can be deformed and vibrated under the influence of an external magnetic field or the like. It can be taken out through the lower metal film central portion 74 and the ferromagnetic film 73 . In the vibrator 70, a voltage is applied to the central portion 72 of the piezoelectric film to generate deformation and vibration, and the ferromagnetic film 73 is deformed and vibrated together with the central portion 72 of the piezoelectric film, thereby suppressing magnetic field fluctuations. can be generated. Thus, the vibrating body 70 has magnetoelectric conversion properties.

As shown in FIG. 3, the support arms 80 are connected to both ends of the vibrating body 70 in the X-axis direction. One end of the support arm portion 80 is connected to the vibrating body 70 , and the other end of the support arm portion 80 is fixed to the upper end 41 a of the fixing portion 41 . Thereby, the supporting arm portion 80 connects the vibrating body 70 to the fixing portion 41a of the substrate 40 so as to vibrate. As shown in FIG. 3, support arm 80 includes lower metal film end 84 and piezoelectric film end 82 .

As shown in FIG. 3, the lower metal film integrally has a lower metal film center portion 74 of the vibrating body 70 and lower metal film end portions 84 that are part of the support arm portions 80 . In plan view shown in FIG. 2, the lower metal film central portion 74 has a substantially rectangular shape smaller than the upper opening of the lower space 40b. Therefore, a gap 94 (see FIGS. 2 and 4) is formed between the lower metal film central portion 74 and the upper opening of the lower space 40b.

Further, as shown in FIG. 3, the lower metal film end portions 84 of the lower metal film are positioned at both ends of the lower metal film central portion 74 in the X-axis direction, and are located further from the central portion 50b than the central portion 50b in plan view shown in FIG. It has a substantially rectangular shape with a small width in the Y-axis direction. Since the lower metal film has the shape as described above, in the cross section shown in FIG. 3, it exists so as to bridge the upper opening of the lower space 40b in the X-axis direction. A portion of the lower metal film end portion 84 of the lower metal film is connected to and fixed to the upper end 41 a of the fixing portion 41 of the substrate 40 .

On the other hand, FIG. 4 is a cross-sectional view taken along line IV--IV in FIG. In FIG. 4, only the cross section of the lower metal film central portion 74 appears, and the lower metal film end portion 84 connected to the fixed portion of the substrate 40 does not appear. Therefore, in the cross section shown in FIG. 4, the vibrating body 70 including the lower metal film central portion 74 appears to be floating above the Z-axis of the lower space 40b. The vibrating body 70 arranged above the lower space 40b may warp due to imbalance in the stress of each film included in the vibrating body 702. It is preferable from the viewpoint of reducing the energy transmission loss at.

As shown in FIG. 3, the piezoelectric film central portion 72 is located above the lower metal film central portion 74 in the Z-axis direction and is the same as the lower metal film central portion 74 or slightly smaller than the lower metal film central portion 74. It has a substantially rectangular plan view shape. In FIG. 2, the planar dimension (area on the XY plane) of the piezoelectric film central portion 72 is smaller than the planar dimension of the lower metal film central portion 74, but the planar dimension of the piezoelectric film central portion 72 may be approximately the same size as the lower metal film central portion 74 . As shown in FIG. 3 , the piezoelectric film is connected to both ends of the piezoelectric film central portion 72 in addition to the piezoelectric film central portion 72 , and the piezoelectric film ends located above the lower metal film end portions 84 are connected to the piezoelectric film central portion 72 . It has a portion 82 . The piezoelectric film end portion 82 constitutes a part of the support arm portion 80 as well as the lower metal film end portion 84 .

Further, as shown in FIG. 3, a ferromagnetic film 73 is present above the central portion 72 of the piezoelectric film in the Z-axis direction, and as shown in FIG. It has a visual shape. The planar dimension of the ferromagnetic film 73 is slightly smaller than the planar dimension of the piezoelectric film central portion 72 . By making the planar dimension of the ferromagnetic film 73 smaller than that of the central portion 72 of the piezoelectric film, the durability of the magnetoelectric transducer 30 tends to be improved. However, the planar dimension of the ferromagnetic film 73 may be approximately the same as the planar dimension of the piezoelectric film central portion 72 .

As shown in FIG. 3, the tip of the first extraction electrode film 51 is connected to the lower metal film end portion 84 on one side (X-axis negative direction side). The rear end of the first lead-out electrode film 51 is connected to the second lead-out electrode film 53 connected to the ferromagnetic film 73 of the vibrating body 70 adjacent to the X-axis negative direction side, and the array element as shown in FIG. configure.

Furthermore, as shown in FIG. 3, the other (X-axis positive direction side) lower metal film end portion 84 is covered with an insulating film 54 together with a part of the piezoelectric film. A second extraction electrode film 53 is formed so as to extend over the insulating film 54 in the X-axis direction, and the tip of the second extraction electrode film 53 is connected to the ferromagnetic film 73 . The rear end of the second lead-out electrode film 53 is connected to the first lead-out electrode film 51 connected to the lower metal film end portion 83 of the vibrating body 70 adjacent in the positive direction of the X-axis. Construct an array element. It should be noted that the presence of the insulating film 54 insulates the second extraction electrode film 53 from the lower metal film 50 shown in FIGS.

As shown in FIG. 1, the plurality of lower spaces 40b formed in the substrate 40 are divided by the fixing portions 41 in the X-axis direction. 5(a) and 5(b) are schematic diagrams showing enlarged peripheral portions of a row of vibrating bodies 70 arranged in the X-axis direction in the magnetoelectric transducer 30 shown in FIG. FIG. 5(a) is a plan view seen from the Z-axis positive direction side, and FIG. 5(b) is a sectional view of a section parallel to the XZ plane. In addition, in FIGS. 5A and 5B, the shapes of the vibrating body 70 and the like are shown in a simplified manner as compared with FIGS.

Further, as shown in FIG. 5(a), at the upper end 41a of the fixed portion 41 of the substrate 40, there are a supporting arm portion 80 connected to the adjacent vibrating body 70 on the negative side of the X-axis and a supporting arm portion 80 on the positive side of the X-axis. A supporting arm portion 80 connected to an adjacent vibrating body 70 is fixed. Thereby, the fixed part 41 supports the vibrating body 70 via the support arm part 80 so as to vibrate.

As shown in FIG. 5B, the fixed portion 41 has a substantially trapezoidal shape in a cross section (longitudinal cross section) perpendicular to the main surface 70a of the vibrating body 70 and parallel to the X-axis direction. FIG. 5(c) shows an enlarged cross-sectional shape of the fixing portion 41 shown in FIG. 5(b).

As shown in FIG. 5C, in the fixed portion 41, a first cross section parallel to the main surface 70a (parallel to the XY plane) of the vibrating body 70 and at a first distance L from the upper end 41a of the fixed portion 41 The cross-sectional area of 42 is narrower than the second cross-section 43 which is parallel to the main surface 70a of the vibrating body 70 and is a second distance L2 from the upper end 41a of the fixed portion 41 longer than the first distance L1.

That is, the fixed portion 41 has a transition change portion in which the cross-sectional area of the cross section parallel to the main surface 70a of the vibrating body 70 transitionally narrows as the distance from the upper end 41a of the fixed portion 41 decreases. As shown in FIGS. 5(b) and 5(c), the fixing portion 41 is entirely a transition changing portion, and the cross section of the fixing portion 41 has a trapezoidal shape. However, the transition change portion whose cross-sectional area becomes narrower as the distance from the upper end 41a decreases may be formed only partially in the height direction of the fixed portion 41 .

Although the angle of inclination of the side surface 41b of the fixed portion 41 with respect to the Z-axis direction is not particularly limited, it is preferably 1 degree to 15 degrees, particularly preferably 3 degrees to 10 degrees. By making the shape of the fixed portion 41 as described above, the plurality of vibrating bodies 70 are arranged close to each other, the rigidity of the fixed portion 41 is increased to prevent the vibration of the fixed portion 41, and the vibration of each vibrating body 70 is suppressed. Independence can be secured. A part of the frame portion 49 of the substrate 40 shown in FIG.

(piezoelectric film)
The piezoelectric film having the piezoelectric film center portion 72 and the piezoelectric film end portions 82 is made of a piezoelectric material and exhibits a piezoelectric effect or an inverse piezoelectric effect. The piezoelectric effect means the effect of generating an electric charge when an external force (stress) is applied, and the inverse piezoelectric effect means the effect of generating strain when a voltage is applied. Examples of piezoelectric materials that exhibit such an effect include crystal, lithium niobate, aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT: Pb(Zr, Ti)O ₃ ), and potassium niobate. Examples include sodium (KNN: (K, Na)NbO ₃ ), barium calcium zirconate titanate (BCZT: (Ba, Ca) (Zr, Ti) O ₃ ), and the like.

In this embodiment, among the above piezoelectric materials, it is particularly preferable to use piezoelectric materials having a perovskite structure such as PZT, KNN, and BCZT. By using a piezoelectric material with a perovskite structure as the piezoelectric film, both excellent piezoelectric characteristics and high reliability can be obtained. It should be noted that other elements may be appropriately added to the above piezoelectric material forming the piezoelectric film 10 in order to improve the characteristics.

The thickness of the piezoelectric film including the piezoelectric film central portion 72 can be, for example, 0.5 to 10 μm. The thickness of the piezoelectric film can be obtained, for example, by image analysis of a cross-sectional photograph. That is, it is preferable to measure the thickness of the piezoelectric film at three or more points in the in-plane direction and calculate the average value. As the piezoelectric film, it is preferable to use a film having a small thickness variation of ±5% or less.

The piezoelectric film may be an epitaxially grown film. An epitaxially grown film means a film epitaxially grown on a single crystal substrate. Here, epitaxial growth means that during film formation, the crystals of the film are aligned with the crystal lattice of the underlying material in the film thickness direction (Z-axis direction) and in-plane directions (X-axis and Y-axis directions). It means growing together. Therefore, the piezoelectric film 10, which is an epitaxially grown film, has a crystal structure in which the crystals are aligned in all three axial directions of the X-axis direction, the Y-axis direction, and the Z-axis direction in a high temperature state during film formation. (epitaxial film), almost no grain boundaries are formed at room temperature after film formation, and it has a crystal structure close to a single crystal (not a perfect single crystal) (epitaxially grown (film)).

When the piezoelectric film is a PZT epitaxially grown film, it preferably contains a total of three domains, two tetragonal domains and a rhombohedral domain. On the other hand, when the piezoelectric film is a KNN epitaxially grown film, it preferably has two types of orthorhombic domains and one type of monoclinic domains (three domains in total). When the piezoelectric film is a BCZT epitaxially grown film, it preferably has two tetragonal domains and two orthorhombic domains (a total of four domains).

The piezoelectric film may not be an epitaxially grown film, and may be a piezoelectric thin film such as PZT, KNN, or BCZT formed by a thin film method other than epitaxial growth.

(ferromagnetic film)
The ferromagnetic film 73 is preferably composed of, for example, a soft magnetic high magnetostrictive film, and generates distortion due to the magnetostrictive effect when a magnetic field, electromagnetic waves, ultrasonic waves, or the like is applied from the outside. The soft magnetic high magnetostrictive film is preferably composed of a soft magnetic material having a low coercive force H _C and a low threshold magnetic field H _TH and having a saturation magnetostriction λ _MAX of 5 ppm or more. The saturation magnetostriction λ _MAX is more preferably 10 ppm or more. The soft magnetic material is generally a low magnetostrictive material with a saturation magnetostriction λ _MAX of 1 ppm or less. It is important to have

Soft magnetic materials having the above characteristics include, for example, iron (Fe)-cobalt (Co)-silicon (Si)-boron (B) alloy, Fe-Si-B alloy, Fe-Co-B alloy, Fe-chromium (Cr)-Si-B alloy, Fe-nickel (Ni)-molybdenum (Mo)-B alloy, Fe-Si-B-copper (Cu)-niobium (Nb) alloy, Co-Fe-Ni- Si--B--Mo alloys and the like are included.

Further, in the present embodiment, the coercive force H _C of the soft magnetic high magnetostrictive film is preferably less than 2500 A/m. The lower the _coercive force HC, the more the responsiveness of the magnetoelectric effect in the magnetoelectric conversion element 30 is improved. However, it is difficult to set the coercive force H 2 _C to 0 A/m, and the lower limit of the coercive force H 2 _C also depends on the specifications of the film forming apparatus used during manufacturing. The coercive force H _C of the soft magnetic high magnetostrictive film is more preferably 1 A/m or more and less than 2500 A/m, and more preferably 1 A/m or more and 1500 A/m or less.

Further, the threshold magnetic field H _TH of the soft high magnetostrictive film is more preferably 1 A/m or more and less than 500 A/m, and more preferably 1 A/m or more and 350 A/m or less. In this embodiment, the threshold magnetic field _HTH means a magnetic field that causes magnetostriction of 0.1 ppm in the soft magnetic high magnetostrictive film. In addition, the magnetic field sensitivity dλ/dH of the soft magnetic high magnetostrictive film is preferably 10 ppb·m·A ⁻¹ or more, more preferably 15 ppb·m·A ⁻¹ or more. In this embodiment, the magnetic field sensitivity dλ/dH means the amount of change in magnetostriction under an environment in which a DC magnetic field of 500 A/m is applied as a bias magnetic field.

The ferromagnetic film 73 preferably contains an amorphous phase and a crystalline phase. Further, it is more preferable that most of the included crystal phases of the ferromagnetic film 73 including an amorphous layer and a crystal layer have a face-centered cubic structure (fcc). However, even in this case, at least a part of the crystal phase may be mixed with a body-centered cubic (bcc) crystal phase.

The thickness of the ferromagnetic film 73 is preferably within the range of 0.1-5 μm. The thickness of the ferromagnetic film 73 is measured in the same manner as the thickness of the central portion 72 of the piezoelectric film. The thickness of the ferromagnetic film 73 also has a small variation in the in-plane direction, and the thickness of the piezoelectric film central portion 72 can be varied to the same degree. In this embodiment, the ratio of the thickness of the ferromagnetic film 73 to the thickness of the piezoelectric film central portion 72 (thickness of the piezoelectric film central portion 72/thickness of the ferromagnetic film 73) is preferably 1/10 to 10. Within range.

(substrate)
The substrate 40 in the magnetoelectric conversion element 30 is composed of an insulating member or the like that supports at least the laminate 32 . For example, the substrate 40 may be a single crystal substrate used for epitaxial growth of the piezoelectric film 10 of the laminate 32 or a substrate used for laminating the portions constituting the laminate 32 by a thin film method or the like. The material of the substrate 40 can be selected from various single crystals such as Si, MgO, strontium titanate (SrTiO ₃ ), and lithium niobate (LiNbO ₃ ). It is preferable to use a silicon substrate having the following structure.

The lower metal film having the lower metal film center portion 74 and the lower metal film end portions 84 is composed of a conductive metal film such as Pt, Ag, Cu, Au, Al. When the piezoelectric film is an epitaxially grown film, the lower metal film is also preferably an epitaxially grown film. As the lower metal film, which is an epitaxially grown film, it is preferable to use a metal thin film with a face-centered cubic structure such as Pt, Ir, or Au, or an oxide conductor film with a perovskite structure such as SrRuO ₃ (SRO) or LaNiO ₃ . . Such a metal thin film and oxide conductor thin film can be epitaxially grown on a single crystal substrate, whereby the lower metal film can also be an epitaxially grown film. Also, the lower metal film may be configured by stacking the above metal thin film and the above oxide conductor film (for example, Pt electrode/SrRuO ₃ or the like). In this case (in the case of multiple layers), the oxide conductor film is preferably present on the piezoelectric film side of the lower metal film (that is, above in the Z-axis direction). The average thickness of the lower metal film is preferably 3 nm to 200 nm as a whole.

As a vibrating body according to a modified example, one in which an upper electrode film is formed between the ferromagnetic film 73 and the piezoelectric film central portion 72 shown in FIG. 3 is also conceivable. When the upper electrode film is formed between the piezoelectric film central portion 72 and the ferromagnetic film 73, the upper electrode film can be made of the same material and thickness as those of the lower metal film central portion 74, for example.

The first extraction electrode film 51 and the second extraction electrode film 53 shown in FIGS. 1 to 4 are composed of conductive films, and the material and thickness thereof are not particularly limited. For example, the first extraction electrode film 51 and the second extraction electrode film 53 can contain conductive metals such as Ag, Cu, Au and Al in addition to Pt. The insulating film 54 shown in FIGS. 1 to 4 is composed of an electrically insulating film, and its material and thickness are not particularly limited. For example, regarding the material of the insulating film 54, SiO ₂ , Al ₂ O ₃ , polyimide, or the like can be used.

As a vibrating body according to a modification, unlike the vibrating body 70 shown in FIG. It is also conceivable that a buffer layer is formed between them. By forming the buffer layer between the substrate 40 and the lower metal film, it is possible to promote the epitaxial growth of the film positioned above the buffer layer. The buffer layer also functions as an etching stopper layer when forming the lower space 40 b in the substrate 40 . When the buffer layer is formed, its thickness is preferably 5 nm to 100 nm.

In the magnetoelectric conversion element 30 shown in FIGS. 1 to 5, the vibrating body 70 functions as a vibrator having a specific frequency vibration mode. That is, the vibrating body 70 can generate in-plane expansion and contraction in which the vibrating body 70 expands and contracts along the XY plane, and is capable of in-plane stretching vibration. Note that the vibrating body 70 can expand and contract not only in-plane but also out-of-plane expansion and contraction in which the vibrating body 70 expands and contracts in the Z-axis direction.

The support arm portion 80 connecting the vibrating body 70 and the fixed portion 41 preferably has a low rigidity with respect to the vibrating body 70 so as not to interfere with the in-plane expansion and contraction of the vibrating body 70 . As shown in FIG. 2, for example, the width of the support arm 80 in the Y-axis direction is narrower than the width of the vibrating body 70 in the Y-axis direction. Alternatively, the Z-axis direction thickness of the support arm portion 80 is made smaller than the Z-axis direction thickness of the vibrating body 70 . The product of the thickness and width of the support arm 80 is preferably less than 90% of that of the vibrating body 70, and more preferably less than 75%. By configuring in this way, an in-plane stretching vibration with a large amplitude can be induced, and the output of the magnetoelectric transducer 30 can be further increased.

Also, the length of the support arm 80 in the X-axis direction is preferably about 1/4 of the vibration wavelength at which the vibrating body 70 operates. With such a length, energy can be efficiently confined in the vibrating body 70 , the output of the magnetoelectric transducer 30 can be increased, and mutual interference between the plurality of vibrating bodies 70 can be suppressed.

5(b) and 5(c) is lower than the resonance frequency at which the vibrating body 70 operates. It is preferable from the viewpoint of ensuring the independence of vibration of 70 . Further, the fundamental resonance frequency of the vibration mode of the fixed portion 41 displaced in the same direction as the vibration direction of the vibration mode in which the vibrating bodies 70 operate is lower than the resonance frequency in which the vibrating bodies 70 operate. This is preferable from the viewpoint of suppressing mutual interference.

An example of a method for manufacturing the magnetoelectric transducer 30 shown in FIGS. 1 to 5 will be described below.

In manufacturing the magnetoelectric conversion element 30, first, a lower metal film to be the lower metal film central portion 74 and the lower metal film end portions 84, the piezoelectric film central portion 72 and the piezoelectric film central portion 72 and the lower metal film end portions 84 are formed on a film formation substrate such as a silicon substrate. A piezoelectric film to be the piezoelectric film end portion 82 and the ferromagnetic film 73 are deposited. Physical or chemical methods such as vapor deposition, sputtering, sol-gel, CVD, and PLD can be used to form the lower metal film, piezoelectric film, and ferromagnetic film. Moreover, when at least a part of the lower metal film, the piezoelectric film and the ferromagnetic film is formed by epitaxial growth, it is preferable to use the sputtering method. When the ferromagnetic film is a magnetic film composed of a soft magnetic high magnetostrictive film, etc., it is formed by a vacuum deposition method such as a sputtering method, a vacuum deposition method, a PLD method, an ion beam deposition method (IBD method), or the like. can be formed, and is preferably formed by a sputtering method.

Furthermore, the lower metal film, the piezoelectric film and the ferromagnetic film 73 formed on the film formation substrate are subjected to patterning processing so as to form patterns as shown in FIGS. The patterning process can be performed by various etching methods such as photoetching and laser dry etching, or by a lift-off method.

After patterning, the first extraction electrode film 51, the second extraction electrode film 53, and the insulating film 54 are formed in a predetermined pattern as shown in FIGS. A portion of the film-forming substrate is removed by dry etching such as Deep-RIE or anisotropic wet etching to form the substrate 40 having the lower space 40b. Note that the deposition substrate may be entirely removed by the above etching. In this case, the vibrating body 70, the support arm 80, the extraction electrode films 51 and 53, and the like peeled off from the film formation substrate may be fixed to the substrate 40 prepared as separate members. Further, a cover portion 90 as shown in FIG. 5B is joined to the upper surface of the substrate 40 to obtain the magnetoelectric transducer 30 shown in FIGS. Although the cover part 90 is provided mainly to protect the vibrating body 70 and the upper space 90a, it may be omitted when the magnetoelectric conversion element 30 is arranged inside the apparatus.

Hereinafter, the magnetoelectric transducer 30 according to the first embodiment will be described in further detail using examples. However, the magnetoelectric transducer 30 is not limited to the examples.

(Example 1)
As the magnetoelectric conversion element 30 according to Example 1, an array type element is manufactured in which a plurality of vibrating bodies 70 as shown in FIGS. did. The plurality of vibrating bodies 70 included in the magnetoelectric conversion element 30 all have the same shape. 200 μm.

Each vibrator 70 includes a piezoelectric film central portion 72 made of PZT formed by epitaxial growth, and a ferromagnetic film 73 made of an Fe—Co—Si—B alloy having a crystalline phase and an amorphous phase. It is composed of a membrane stack. The thickness of the central portion 72 of the piezoelectric film was 1 μm, and the thickness of the ferromagnetic film 73 was 0.5 μm. The height of the fixing portion 41 shown in FIG. 5C (the distance from the surface of the substrate 40 on the Z-axis positive direction side to the upper end 41a of the fixing portion 41) was 300 μm.

The number of vibrating bodies 70 included in the magnetoelectric conversion element 30 according to the first embodiment is 45. The 45 vibrating bodies 70 are arranged along the X-axis direction and the Y-axis direction, and each vibrating body 70 is arranged in series. wired. The overall dimensions of the magnetoelectric transducer 30 were 1 cm×1 cm.

In Example 1, the side surface 41b of the fixed portion 41 shown in FIG. 5(c) was formed at an angle inclined by 5 degrees (target angle) from the Z-axis direction. The inclination of the side surface 41b is the output of protective film formation and silicon etching, which are known adjustment methods in etching, when deep silicon etching is performed from the back surface of the substrate 40 (the surface on the Z-axis negative direction side) by the Deep-RIE method. and by adjusting the time. The shape of the side surface 41b of the fixed part 41 was measured by taking out a part of the sample prepared at the same time as the sample according to the example and observing the cross section with an operating microscope.

As a magnetoelectric conversion element according to a comparative example, a magnetoelectric conversion element was manufactured in which only the shape of the fixing portion on the substrate was different and the remaining portions were the same. The magnetoelectric conversion element according to the comparative example differs from the magnetoelectric conversion element 30 according to the embodiment only in that the fixed portion has a rectangular cross section and the side surface of the fixed portion rises substantially parallel to the Z-axis direction.

(shape evaluation)
The shape of the fixed portion 41 of the substrate 40 in the magnetoelectric transducer 30 according to Example 1 was measured. The cross-sectional shape of the fixed portion 41 along the XZ cross-section was substantially trapezoidal as shown in FIG. 5(c). The inclination angle of the side surface 41b of the fixed portion 41 with respect to the Z-axis direction was 5 degrees (error ±1 degree). The width of the fixing portion 41 in the X-axis direction is 100 μm at the same height as the upper end 41 a to which the support arm portion 80 is fixed, and 150 μm at the lower end 41 c at the same height as the Z-axis negative direction end of the substrate 40 . rice field. Moreover, the length of the fixed portion 41 in the Y-axis direction was 300 μm at both the heights of the upper end 41a and the lower end 41c.

That is, in the magnetoelectric conversion element 30 according to Example 1, the cross-sectional area of the first cross section 42, which is the first distance L1 (L1=0 μm) from the upper end 41a, is 3000 μm ² , and the second distance L2 from the upper end 41a. The cross-sectional area of the second cross section 43 (L2=300 μm) was 4500 μm ² . As described above, the fixed portion 41 of the magnetoelectric transducer 30 according to the first embodiment has a cross-sectional area parallel to the main surface 70a of the vibrating body 70, and the distance from the upper end 41a of the fixed portion 41 is small. It was confirmed that it narrows transitionally according to

On the other hand, in the magnetoelectric conversion element according to Comparative Example 1, the fixed portion had a substantially rectangular cross-sectional shape, and the inclination angle of the side surface of the fixed portion with respect to the Z-axis direction was 0 degree (error ±1 degree). In addition, in the magnetoelectric conversion element according to Comparative Example 1, the cross-sectional area of the cross section parallel to the main surface 70a of the vibrating body was the same 3000 μm ² at the upper end and the lower end of the fixing portion.

(Measurement of resonance frequency)
The vibration characteristics of the vibrating bodies 70 of the magnetoelectric transducer 30 according to Example 1 and the magnetoelectric transducer according to Comparative Example 1 were measured by an impedance analyzer. As a result, it was confirmed that both the vibrating bodies 70 of Example 1 and Comparative Example 1 had an operating resonance frequency of 5 MHz, and were bulk acoustic wave vibrators that vibrate elastic waves in a spreading vibration. The vibration direction of the vibration mode in which the vibrating body 70 vibrates elastically with spreading vibration is the in-plane horizontal direction.

In the magnetoelectric conversion element 30 according to Example 1, the primary resonance frequency (eigenfrequency) of the fixed portion 41 was 120 kHz, so it was confirmed that the resonance frequency at which the vibrating body 70 operates was lower than 5 MHz. rice field. Further, the primary resonance frequency of the fixed portion 41 was in a vibration mode in which displacement occurred in the in-plane horizontal direction, which is the same direction as the vibration mode in which the vibrating body 70 operates. Therefore, in the magnetoelectric transducer 30 according to the first embodiment, the fundamental resonance frequency (120 KHz) of the vibration mode of the fixed portion 41 displaced in the same direction as the vibration direction of the vibration mode in which the vibrating body 70 operates is equal to that of the vibrating body 70. was confirmed to be lower than the operating resonant frequency (5 MHz).

(Measurement of output voltage)
For the magnetoelectric conversion element 30 according to Example 1 and the magnetoelectric conversion element according to Comparative Example 1, a magnetic field of 5 MHz, which is the same frequency as the resonance frequency at which the vibrating body 70 operates, was applied, and the output of each element was measured. . As a result, the magnetoelectric transducer 30 according to Example 1 detected an output voltage of 50 mV, while the magnetoelectric transducer according to Comparative Example 1 detected an output voltage of 30 mV.

Second Embodiment FIGS. 6A and 6B are schematic diagrams showing a part of a magnetoelectric conversion element 130 according to a second embodiment, and relate to a magnetoelectric conversion element 30 according to the first embodiment. This corresponds to FIGS. 5(a) and 5(b). FIG. 6(a) is a plan view seen from the Z-axis positive direction side, and FIG. 6(b) is a sectional view of a section parallel to the XZ plane. In addition, in FIG. 6A, the cover portion 90 shown in FIG. 6B is omitted for convenience of explanation.

As shown in FIGS. 6(a) and 6(b), in the magnetoelectric conversion element 130 according to the second embodiment, the fixed portion of the substrate 140 is each vibrator 70 in the cross-sectional view shown in FIG. 6(b). and a fixed portion common bottom portion 146 that connects a plurality of fixed portion upper portions 141 below the fixed portion upper portion 141 (Z-axis negative direction). Although different from the magnetoelectric transducer 30 according to the first embodiment, parts other than the substrate 140 are the same as the magnetoelectric transducer 30 shown in FIGS. 5(a) and 5(b). The magnetoelectric conversion element 130 according to the second embodiment will be described with a focus on the differences from the magnetoelectric conversion element 30 according to the first embodiment, and the description of the common points with the magnetoelectric conversion element 30 will be omitted. do.

As shown in FIG. 6A, the support arm portion 80 connected to the vibrating body 70 is fixed to the upper end 141a of the fixed portion upper portion 141, and the fixed portion upper portion 141 vibrates via the support arm portion 80. It supports the body 70 so that it can vibrate. However, while the fixed portion 41 shown in FIG. and is spaced from connection 148 .

The substrate 140 is formed with a plurality of lower spaces 140b between which at least part of the fixing portion 140 (fixing portion upper portion 141) is arranged. As shown in FIG. 6B, the lower end of the fixed part upper part 141 is connected to the fixed part common bottom part 146 . In other words, the plurality of fixing part upper parts 141 protrude upward from the upper surface of the fixing part common bottom part 146 , and the supporting arm part 80 is fixed to the upper ends 141 a of the fixing part upper parts 141 . Further, the fixing portion upper portion 141 and the fixing portion common bottom portion 146 are made of a common material such as Si, and form an integral member having no joint portion.

As shown in FIG. 6B, the fixing portion upper portion 141 has a substantially trapezoidal shape in a cross section (longitudinal cross section) perpendicular to the main surface 70a of the vibrating body and parallel to the X-axis direction. Therefore, similarly to the fixed portion 41 shown in FIG. 6(c), the fixed portion upper portion 141 has a cross-sectional area of a first cross section that is a first distance from the upper end 141a, and a second cross-sectional area longer than the first distance from the upper end 141a. is narrower than the second section, which is the distance of

The magnetoelectric conversion element 130 according to the second embodiment also has the same effects as the magnetoelectric conversion element 30 according to the first embodiment.

Third Embodiment FIGS. 7A and 7B are schematic diagrams showing a part of a magnetoelectric conversion element 230 according to a third embodiment, and relate to a magnetoelectric conversion element 130 according to a second embodiment. This corresponds to FIGS. 6(a) and 6(b). FIG. 7(a) is a plan view seen from the Z-axis positive direction side, and FIG. 7(b) is a sectional view of a section parallel to the XZ plane. 7A, the cover portion 90 shown in FIG. 7B is omitted for convenience of explanation.

As shown in FIGS. 7(a) and 7(b), the magnetoelectric conversion element 230 according to the third embodiment has a fixed portion upper portion 241 different from the fixed portion upper portion 141 shown in FIG. 6(b). , and the other points are the same as those of the magnetoelectric transducer 130 according to the second embodiment. The magnetoelectric conversion element 230 according to the third embodiment will be described with a focus on the differences from the magnetoelectric conversion element 130 according to the second embodiment, and the description of the common points with the magnetoelectric conversion element 130 will be omitted. do.

As shown in FIG. 7A, the support arm portion 80 connected to the vibrating body 70 is fixed to the upper end 241a of the fixed portion upper portion 241 on the substrate 240, and the fixed portion upper portion 241 to support the vibrating body 70 so as to vibrate. As shown in FIG. 7(b), the lower end of the fixing portion upper portion 241 is connected to the fixing portion common bottom portion 146, but unlike the fixing portion upper portion 141 shown in FIG. , and is made of a material having a higher specific gravity than the common bottom portion 146 of the fixed portion.

The fixing part upper part 241 shown in FIG. 7B is manufactured, for example, by joining the fixing part upper part 241 made of a different material to the upper surface of the flat fixing part common bottom part 146, or by bonding the fixing part upper part 241 made of a different material. can be produced by forming a thin film of

In the magnetoelectric transducer 230 according to the third embodiment, since the specific gravity of the fixed upper portion 241 that supports the vibrating body 70 is greater than the other portions of the substrate 40, vibration of the fixed upper portion 241 can be prevented. can. In addition, the magnetoelectric conversion element 230 according to the third embodiment has the same effects as the magnetoelectric conversion element 130 in common with the magnetoelectric conversion element 130 according to the second embodiment.

Fourth Embodiment FIG. 8 is a schematic cross-sectional view showing part of a magnetoelectric conversion element 330 according to a fourth embodiment, and corresponds to FIG. 6B regarding the magnetoelectric conversion element 130 according to the second embodiment. . FIG. 8 is a cross-sectional view of the magnetoelectric transducer 330 taken parallel to the XZ plane.

As shown in FIG. 8, in the magnetoelectric transducer 330 according to the fourth embodiment, the shape of the fixed portion upper portion 341 on the substrate 340 is different from the fixed portion upper portion 141 shown in FIG. This is the same as the magnetoelectric transducer 130 according to the second embodiment. The magnetoelectric conversion element 330 according to the fourth embodiment will be described with a focus on the differences from the magnetoelectric conversion element 130 according to the second embodiment, and the description of the common points with the magnetoelectric conversion element 130 will be omitted. do.

As shown in FIG. 8, in the magnetoelectric conversion element 330 according to the fourth embodiment, at least a portion of the side surface 341c of the upper fixing portion 341 is curved. As described above, even when the side surface 341c of the fixed portion upper portion 341 is curved, it is similar to the case where the side surface of the fixed portion upper portion 141 is planar like the magnetoelectric conversion element 130 shown in FIG. In addition, the rigidity of the fixed portion upper portion 341 can be increased, and the vibration of the fixed portion upper portion 341 can be prevented. In addition, the magnetoelectric conversion element 330 according to the fourth embodiment has the same effects as the magnetoelectric conversion element 130 in common with the magnetoelectric conversion element 130 according to the second embodiment.

Fifth Embodiment FIG. 9 is a schematic diagram showing a part of the magnetoelectric conversion element 430 according to the fifth embodiment, and corresponds to FIG. 5B regarding the magnetoelectric conversion element 30 according to the first embodiment. FIG. 9 is a cross-sectional view taken parallel to the XZ plane.

As shown in FIG. 9, in a magnetoelectric conversion element 430 according to the fifth embodiment, a fixed portion of a substrate 440 divides a lower space 440b corresponding to each vibrating body 70 in the X-axis direction. It is different from the magnetoelectric conversion element 30 according to the first embodiment in that it has a fixed portion common bottom portion 446 that connects the fixed portion upper portion 441 below the fixed portion upper portion 141 (negative direction of the Z axis). Parts other than the substrate 440 are the same as those of the magnetoelectric transducer 30 shown in FIG. 5(b). Regarding the magnetoelectric conversion element 430 according to the fifth embodiment, the description will focus on the points of difference from the magnetoelectric conversion element 30 according to the first embodiment, and the description of the common points with the magnetoelectric conversion element 30 will be omitted. do.

In the magnetoelectric conversion element 430 , the upper fixing portion 441 supports the vibrating body 70 through the support arm portion 80 so as to vibrate. As shown in FIG. 9 , the lower end of the fixed portion upper portion 441 is connected to the fixed portion common bottom portion 446 . In other words, the plurality of fixing portion upper portions 441 protrude upward from the upper surface of the fixing portion common bottom portion 446 , and the support arm portion 80 is fixed to the upper ends 141 a of the fixing portion upper portions 441 .

As shown in FIG. 9, in the fixing portion upper portion 441, the cross-sectional area of the cross section (first cross section) parallel to the main surface 70a of the vibrating body 70 is constant. However, the cross-sectional area of the first cross section in the fixed portion upper portion 141 is the cross-sectional area of the second cross section parallel to the main surface 70a of the vibrating body 70 in the fixed portion common bottom portion 446 and having a longer distance from the upper end 441a than the first cross section. narrower. The fixed portion of the magnetoelectric conversion element 430 has increased rigidity due to the wide cross-sectional area of the fixed portion common bottom portion 446, and can prevent vibration.

The fixing portion of the substrate 440 includes a side surface 441c (first side surface) of the fixing portion upper portion 441 as a first portion including the first cross section and a side surface of the fixing portion common bottom portion 446 as a second portion including the second cross section. 446a (second side surface) is provided. In the cross section shown in FIG. 9, the step surface 447 constitutes the bottom surface of the lower space 440b.

The magnetoelectric conversion element 430 according to the fifth embodiment also exhibits the same effects as the magnetoelectric conversion element 30 in common with the magnetoelectric conversion element 30 according to the first embodiment.

Sixth Embodiment FIG. 10 is a schematic cross-sectional view showing part of a magnetoelectric transducer 530 according to a sixth embodiment, and corresponds to FIG. 9 regarding the magnetoelectric transducer 430 according to the fifth embodiment. FIG. 10 is a cross-sectional view of the magnetoelectric transducer 530 taken parallel to the XZ plane.

As shown in FIG. 10, a magnetoelectric conversion element 530 according to the sixth embodiment differs from the cover part 90 shown in FIG. It is similar to the magnetoelectric transducer 430 . The magnetoelectric conversion element 530 according to the sixth embodiment will be described with a focus on the differences from the magnetoelectric conversion element 430 according to the fifth embodiment, and the description of the common points with the magnetoelectric conversion element 430 will be omitted. do.

As shown in FIG. 10, the cover portion 590 of the magnetoelectric conversion element 530 according to the sixth embodiment has a cover portion columnar portion 590c extending downward from a cover portion upper portion 590b. The lower end of the cover column portion 590c is connected to the upper end 441a of the fixed portion upper portion 441, and the upper space 590a above two adjacent vibrating bodies 70 is partitioned by the cover portion column portion 590c. The magnetoelectric conversion element 530 having such a cover portion 590 has a structure in which an upper space 590 a and a lower space 440 b for accommodating the vibrating bodies 70 are separated for each vibrating body 70 .

The magnetoelectric conversion element 530 according to the sixth embodiment has the same effects as the magnetoelectric conversion element 430 in common with the magnetoelectric conversion element 430 according to the fifth embodiment.

Seventh Embodiment FIG. 11 is a schematic cross-sectional view showing part of a magnetoelectric transducer 630 according to a seventh embodiment, and corresponds to FIG. 9 regarding the magnetoelectric transducer 430 according to the fifth embodiment. FIG. 11 is a cross-sectional view of the magnetoelectric transducer 530 taken parallel to the XZ plane.

As shown in FIG. 11, the magnetoelectric transducer 630 according to the seventh embodiment is different from the magnetoelectric transducer 430 according to the sixth embodiment in that it has a case portion 690 instead of the cover portion 90 shown in FIG. , but similar to the magnetoelectric transducer 430 in other respects. Regarding the magnetoelectric conversion element 630 according to the seventh embodiment, the description will focus on the points of difference from the magnetoelectric conversion element 430 according to the fifth embodiment, and the description of the common points with the magnetoelectric conversion element 430 will be omitted. do.

As shown in FIG. 11, the magnetoelectric conversion element 630 according to the seventh embodiment has a case portion 690 that accommodates the vibrating body 70 and the substrate 440 instead of the cover portion 590 . Case portion 690 has a case bottom portion 690c that supports the bottom surface of substrate 440 and a case top portion 690b that covers the sides and top of substrate 440 and vibrating body .

Case portion 690 forms a housing space inside by combining case bottom portion 690c and case top portion 690b, and other members such as vibrating body 70 and substrate 440 are arranged in the housing space.

The magnetoelectric conversion element 630 according to the seventh embodiment has the same effects as the magnetoelectric conversion element 430 in common with the magnetoelectric conversion element 430 according to the fifth embodiment.

Although the present invention has been described above with reference to the embodiments and examples, the laminate according to the present invention is not limited to the above-described embodiments and examples, and may include other embodiments and modifications. Needless to say.

For example, although the vibrating body 70 has a substantially rectangular plan view shape, the shape of the vibrating body 70 is not limited to this, and may be an elliptical, circular, meandering, or spiral plan view shape. There may be. Similarly, the shape of the support arm portion 80 is not limited to a substantially rectangular (belt-shaped) plan view shape, and may be a meander shape, a crank shape, a donut shape (hollow circle or polygon), or an arc shape when viewed in plan view. good. Also, the arrangement of the plurality of vibrating bodies 70 is not limited to the matrix-like arrangement shown in FIG. 1, but may be arranged concentrically or radially.

30, 130, 230, 330, 430, 530, 630... Magnetoelectric transducer 40, 140, 240, 340, 440... Substrate 41... Fixed part 41a, 141a, 241a... Upper end 41b... Side surface 41c... Lower end 42... First Section L1 First distance 43 Second section L2 Second distance 48, 148 Connecting portion 49 Frame 40b, 140b Lower space 70 Vibrating body 70a Principal surface 72 Piezoelectric film central portion 73 Ferromagnetic film 74 Lower metal film central portion 80 Supporting arm 82 Piezoelectric film end 84 Lower metal film end 51 First extraction electrode film 53 Second extraction electrode film 54 Insulating film 90, 590... Cover part 90a, 590a... Upper space 94... Gap 96... Wiring part 141, 241, 341, 441... Upper part of fixing part 146, 446... Common bottom part of fixing part 341c, 441c... Side surface of upper part of fixing part 446a... Common to fixing part Bottom side surface 447 Stepped surface 590b Upper part of cover part 590c Column part of cover part 690 Case part 690b Upper part of case 690c Bottom part of case

Claims (6)

a substrate having a plurality of lower spaces between which at least part of the fixing part is arranged;
a plurality of vibrating bodies provided corresponding to the lower space, supported vibratably in the lower space via support arms connected to the fixing portion, and having magnetoelectric conversion properties;
each of the lower spaces is connected to an upper space above the vibrating body through a gap between the corresponding vibrating body and the substrate;
A cross-sectional area of a first cross section that is parallel to the main surface of the vibrating body in the fixing portion and is a first distance from the upper end of the fixing portion is parallel to the main surface of the vibrating body in the fixing portion. A magnetoelectric conversion element, wherein the cross-sectional area of a second cross section, which is a second distance longer than the first distance from the upper end of the fixing portion, is narrower than the cross-sectional area of the second cross section. 2. A magnetoelectric conversion element according to claim 1, wherein a primary resonance frequency of said fixed portion is lower than a resonance frequency at which said vibrator operates. 2. The magnetoelectric converter according to claim 1, wherein the fundamental resonance frequency of the vibration mode of the fixed portion displaced in the same direction as the vibration direction of the vibration mode in which the vibrator operates is lower than the resonance frequency in which the vibrator operates. element. The fixing portion has a transition changing portion in which a cross-sectional area of a section parallel to the main surface of the vibrating body in the fixing portion transitionally narrows as the distance from the upper end of the fixing portion decreases. A magnetoelectric transducer according to any one of claims 1 to 3. The fixing portion has a stepped surface connecting a first side surface of the first portion including the first cross section and a second side surface of the second portion including the second cross section. A magnetoelectric transducer according to any one of the above. 6. The magnetoelectric transducer according to claim 1, wherein said vibrating body has a film lamination portion including a piezoelectric film and a ferromagnetic film.

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