JP2005217377A - Element with giant magnetic reluctance effect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element with a giant magnetic reluctance effect which an S/N ratio and durability are improved in a large ratio of MR(magnetic reluctance) change. <P>SOLUTION: The element of the giant magnetic reluctance effect is equipped with a paramagnetic conduction layer 56 which is laminated between a magnetization fixed layer 52 and a magnetization free layer 60 and has an oxide layer expressed by a formula M<SB>x-y</SB>A<SB>y</SB>DO<SB>3-z</SB>. Where, M is an element selected among group I elements in an element periodic table and thallium, A is an element selected among group II elements, and D is an element selected among group VA elements and group VIA elements, and x, y, and z meet 0.1≤x≤1.4, 0≤y≤0.5x, and 0≤z≤0.7, respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a giant magnetoresistive element having a structure in which a sense current flows in a direction perpendicular to the film surface of a magnetoresistive film.

  In recent years, the density of magnetic recording / reproducing apparatuses such as hard disks (HDD) has been rapidly increased. As the recording density of the magnetic recording / reproducing apparatus increases, the recording bit size on the recording medium decreases and the signal magnetic field decreases. In the conventional magnetic head, the signal magnetic field from the recording medium is detected by the electromagnetic induction effect, but sufficient detection sensitivity can no longer be ensured.

  On the other hand, at present, a magnetic head using a spin valve type giant magnetoresistive element (hereinafter referred to as a GMR element) that generates a giant magnetoresistive effect is mainly used. The magnetoresistive layer of the GMR element has a laminated structure of a fixed magnetization layer / intermediate layer / magnetization free layer, and exhibits a very large magnetoresistance effect. A magnetic metal such as cobalt (Co) or cobalt iron (CoFe) is used for the magnetization fixed layer and the magnetization free layer, and a paramagnetic metal such as copper (Cu) is used for the intermediate layer. Although the magnetization direction of the magnetization fixed layer is fixed, the magnetization direction of the magnetization free layer is changed by an external magnetic field signal. The spin of conduction electrons flowing through the intermediate layer has two directions, for example, up and down. For example, if the magnetization directions of the magnetization fixed layer and the magnetization free layer are parallel, the conduction electrons of the spin parallel to the magnetization direction are unlikely to be scattered at the interface between the intermediate layer, the magnetization fixed layer, and the magnetization free layer. On the other hand, when the magnetization direction of the magnetization free layer is antiparallel to the magnetization pinned layer, the spin conduction electrons in both directions are likely to be scattered at the interface. Therefore, in the magnetoresistive effect layer, the electrical resistivity greatly increases when the magnetization directions of the magnetization fixed layer and the magnetization free layer are antiparallel, so that the magnetoresistance (MR) change rate is improved.

  As the magnetoresistive effect layer, a so-called in-plane energization (CIP) type configuration in which a sense current is passed in the in-plane direction of the magnetoresistive effect layer by a pair of electrodes is generally used. The CIP type magnetic head employs a shield type configuration in which a magnetoresistive layer is provided between a pair of magnetic shields made of a ferromagnetic material via a magnetic gap made of an insulator.

  In the magnetic storage system of the in-plane magnetic recording system, the recording density is approaching the limit due to thermal disturbance. Therefore, a perpendicular magnetic recording system that is resistant to thermal disturbance is considered promising, and a system in which various perpendicular recording media and shielded CIP magnetic heads are combined has been proposed. However, in the CIP type magnetic head, since the element size decreases and the reproduction output decreases due to the increase in the storage density, the recording density reaches the theoretical limit at about 100 Gbpsi.

  Recently, a so-called vertical energization (CPP) type magnetic head in which a sense current is energized in a direction perpendicular to the magnetoresistive layer surface from a pair of electrodes has been proposed. The CPP type magnetic head can be miniaturized and can reach a higher recording density. Therefore, development for practical application of the CPP type magnetic head is currently in progress.

In addition, a CPP type magnetic head using a tunnel magnetoresistive effect (TMR) element using an insulating layer as a part of an intermediate layer of the magnetoresistive effect layer has been developed. The TMR element has a large electric resistivity and a large MR change rate compared to the CIP type GMR element. Furthermore, a current confinement (CCP) type GMR element that narrows a current path by using a nano oxide layer (NOL) in which an insulating layer having a small metal hole is embedded in a part of an intermediate layer has been attempted ( For example, see Patent Document 1). The CCP-type GMR element is effective for increasing the electrical resistivity, like the TMR element. In addition, since the sense current concentrates and passes through the interface between the intermediate layer and the ferromagnetic layer, the interface scattering effect is emphasized and the MR change rate reaches a considerable level. At present, the CCP type GMR element is most practical in terms of performance.
Japanese Patent Laid-Open No. 6-21529 (page 4-5, FIG. 1)

  However, since the magnetoresistive layer of the GMR element of the CPP type magnetic head uses an extremely thin metal laminated film as an intermediate layer, the value of electric resistivity is extremely small and it is difficult to obtain a sufficient gain. In order to increase the value of electrical resistivity of the magnetoresistive effect layer and increase the MR change rate, there are some in which GMR elements are stacked in multiple layers. However, if GMR elements are multiplexed, the recording density is lowered, which is not an essential solution. In addition, since the TMR element uses an insulating layer as an intermediate layer, the electrical resistivity is large and a sufficient MR ratio can be realized, but the noise is extremely high and a sufficient signal-to-noise (S / N) ratio can be obtained. Absent. Furthermore, the CCP-type GMR element has a drawback that it is inferior in durability such as electric resistance due to Joule heat generated in a narrowed current path.

  An object of the present invention is to solve such problems and provide a GMR element having a magnetoresistive effect layer that can realize a good S / N ratio with a large MR change rate and improve durability.

In order to solve the above problem, an aspect of the present invention is laminated between a magnetization pinned layer and a magnetization free layer, and M _xy A _y DO _3-z (where M is a group I element of the periodic table of elements and thallium). An element selected from among them, A is an element selected from Group II elements, D is an element selected from Group VA elements and Group VIA elements, and x, y, and z are each 0.1% ≦ x ≦ 1.4, 0 ≦ y ≦ 0.5 · x, and 0 ≦ z ≦ 0.7.) A giant magnetoresistive element having a paramagnetic conductive layer having an oxide layer represented by: Is the gist.

  According to the present invention, it is possible to provide a GMR element having a magnetoresistive effect layer that can realize a good S / N ratio with a large MR change rate and improve durability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  As shown in FIG. 1, the GMR element according to the embodiment of the present invention is provided on a lower electrode layer 74, an antiferromagnetic layer 76 provided on the lower electrode layer 74, and an antiferromagnetic layer 76. The magnetoresistive effect layer 50 and the upper electrode layer 80 provided on the magnetoresistive effect layer 50 are provided. The magnetoresistive effect layer 50 and the antiferromagnetic layer 76 have side surfaces inclined in a trapezoidal shape from the upper electrode layer 80 toward the lower electrode layer 74. An insulating layer 62 is provided from the side surfaces of the magnetoresistive effect layer 50 and the antiferromagnetic layer 76 along the surface of the lower electrode layer 74. In a region outside the trapezoidal magnetoresistive effect layer 50 and the antiferromagnetic layer 76, a hard magnetic layer 64 is provided via an insulating layer 62 between the upper electrode layer 80 and the lower electrode layer 74. The magnetoresistive effect layer 50 includes a fixed magnetization layer 52, an intermediate layer 51, and a free magnetization layer 60 that are sequentially stacked on the antiferromagnetic layer 76. The intermediate layer 51 includes a magnetic coupling blocking layer 54, a paramagnetic conductive layer 56, and an interface adjustment layer 58 that are sequentially stacked on the magnetization pinned layer 52.

  The lower electrode layer 74 and the upper electrode layer 80 are formed so as to be electrically connected to the magnetization fixed layer 53 and the magnetization free layer 60, respectively, and to pass a current in a direction perpendicular to the film surface with respect to the magnetoresistive effect layer 50. Has been.

The antiferromagnetic layer 76 is an antiferromagnetic material such as manganese platinum (MnPt). The magnetization pinned layer 52 and the magnetization free layer 60 are magnetic materials such as CoFe. The magnetic coupling blocking layer 54 and the interface adjustment layer 58 of the intermediate layer 51 are paramagnetic substances such as Cu, and the paramagnetic conductive layer 56 is a one-dimensional electric conductor such as rubidium molybdenum oxide (Rb _0.3 MoO ₃ ). This is an oxide layer of a composite oxide having properties. The insulating layer 62 is an insulator such as alumina (Al ₂ O ₃ ), and the hard magnetic layer 64 is a ferromagnetic material such as cobalt platinum (CoPt).

  The magnetization pinned layer 52 is exchange-coupled with the antiferromagnetic layer 76 so that the magnetization is fixed in a predetermined direction. The intermediate layer 51 including the magnetic coupling blocking layer 54 functions as a spacer layer that blocks the magnetic coupling between the magnetization fixed layer 52 and the magnetization free layer 60. The magnetization free layer 60 is fixed to the magnetization direction weakly by the hard magnetic layer 64 to such an extent that the magnetization direction can be changed under the influence of an external magnetic field. For example, in response to an external magnetic field signal, the magnetization direction of the magnetization free layer 60 is controlled to be switched 180 degrees in a direction orthogonal to the magnetization direction of the magnetization pinned layer 52.

For example, as shown in FIG. 2A, the paramagnetic conductive layer 56 is a complex oxide composed of a first atom M, a second atom D, and an oxygen (O) atom. The first atoms M form a chain that is one-dimensionally connected along the crystal axis in the vertical direction of the drawing. A plurality of octahedral DO ₆ of one second atom D and six O atoms are combined to form a chain parallel to the chain of the first atom M. Further, the first atom M chain and the octahedral DO ₆ chain are alternately arranged. As shown in FIG. 2B, the second atom D is arranged at the center of the octahedron, and O is arranged at each vertex of the octahedron. The crystal structure of the complex oxide is a monoclinic system, and the crystal axis in the chain arrangement direction is the b axis. For example, the composite oxide shown in FIG. 2A can be expressed as M _0.3 DO ₃ . The first and second atoms M and D are monovalent and trivalent cations, respectively, and O is a divalent anion. For example, if the paramagnetic conductive layer 56 is an Rb _0.3 MoO ₃ composite oxide, the first atom M is Rb and the second atom D is Mo. In the Rb _0.3 MoO ₃ composite oxide, Mo is oxygen six-coordinated.

  The GMR element according to the embodiment of the present invention is a CPP type, and a sense current is passed between the upper electrode layer 80 and the lower electrode layer 74 in the stacking direction of each layer of the magnetoresistive effect layer 50 shown in FIG. The The conductive path in the complex oxide crystal used for the paramagnetic conductive layer 56 of the magnetoresistive effect layer 50 is in a chain of first atoms M arranged along the b-axis shown in FIG. For this reason, the oxide layer of the complex oxide crystal exhibits the properties of a one-dimensional electrical conductor. The oxide layer is formed so that the b-axis is perpendicular to the opposing surfaces of the magnetic coupling blocking layer 54 and the interface adjustment layer 58.

  In the embodiment of the present invention, Rb and Mo are used as the elements of the first and second atoms M and D shown in FIGS. 2 (a) and 2 (b). However, the first and second atoms M and D are not limited to the above elements. For example, as the first atom M, in addition to Rb, any of group I elements such as sodium (Na), potassium (K), Cu, silver (Ag), and metal elements such as thallium (Tl) may be used. Good. As the second atom D, in addition to Mo, any one of VA group elements such as vanadium (V) and niobium (Nb) and metal elements of VIA group elements such as tungsten (W) may be used. In addition, the group I element which is the first atom M and the metal element such as Tl are any of metals including group II elements such as magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba). At least one of the elements may be added in a molar ratio of 0.5 or less. In addition to O, O includes VIB group elements such as sulfur (S), selenium (Se), tellurium (Te), and VIIB group elements such as fluorine (F), chlorine (Cl), and bromine (Br). At least one of them may be added. The number of moles of the first atoms M and O may be in the range of 0.1 to 1.4 and 2.3 to 3, respectively, while the second atom D is 1 mole.

For example, when the group II element added to the first atom M is “A”, the composite oxide used for the paramagnetic conductive layer 56 is expressed as M _xy A _y DO ₃ -z. Here, x, y, and z satisfy 0.1 ≦ x ≦ 1.4, 0 ≦ y ≦ 0.5 · x, and 0 ≦ z ≦ 0.7, respectively.

In the case of a conventional TMR element, the sense current passes through an insulating layer such as Al ₂ O ₃ used for the intermediate layer by tunneling. On the other hand, in the GMR element according to the embodiment of the present invention, the composite oxide of the paramagnetic conductive layer 56 shown in FIG. 1 is a one-dimensional electric conductor, which is significantly more conductive than Al ₂ O _3. The degree is great. However, the composite oxide has a large semiconductor resistance and a resistance of about 2 to 3 digits compared to a single metal. Further, the Fermi level of the composite oxide is lower by about 2 to 3 times the thermal energy at room temperature or lower than the work function of Cu. Thus, since the Fermi level of the paramagnetic conductive layer 56 which is a composite oxide is slightly lower than that of the Cu magnetic coupling blocking layer 54 and the interface adjustment layer 58, the paramagnetic conductive layer 56, the magnetic coupling blocking layer 54 and the interface are separated. The potential barrier is not formed at the junction with the adjustment layer 58 and exhibits ohmic characteristics. In addition, since the composite oxide is a one-dimensional electrical conductor, the density of states of electrons on the Fermi surface is large and the bandwidth is small at the same time. For this reason, the ratio of the transition probability between the same spins of electrons and the transition probability between different spins increases. As a result, the MR change rate of the GMR element according to the embodiment of the present invention increases.

  As described above, the oxide layer used for the paramagnetic conductive layer 56 according to the embodiment of the present invention is a one-dimensional electrical conductor and has semiconductor characteristics. Therefore, the electrical resistivity of the intermediate layer 51 having the paramagnetic conductive layer 56 can be made larger than that of Cu used for the intermediate layer of the conventional GMR element. Further, since there is no potential barrier at the junction of the paramagnetic conductive layer 56, the magnetic coupling blocking layer 54, and the interface adjustment layer 58, the contact resistance is negligible, and the electric resistance value of the intermediate layer 51 is equal to the paramagnetic conductive layer 56. It is calculated | required by the electrical resistivity of the oxide layer to be used.

In addition, compared with a conventional TMR element using an insulating layer such as Al ₂ O _3, the electrical resistivity of the intermediate layer 51 using a composite oxide for the paramagnetic conductive layer 56 has a moderate magnitude, and the intermediate layer It is possible to suppress the noise generated at 51. In the embodiment of the present invention, the sense current passes through the intermediate layer 51 without being narrowed in the direction perpendicular to the magnetoresistive effect layer 50 shown in FIG. Deterioration of durability is suppressed.

  In the conventional CIP type GMR element, a large MR ratio is obtained by using Cu for the intermediate layer. The work function of Cu of the intermediate layer and Co or CoFe used for the magnetization fixed layer and the magnetization free layer sandwiching the intermediate layer is about 4.5 eV. For example, it has been found that the MR change rate is small when a metal having a work function significantly different from about 4 eV, such as titanium (Ti), is used for the intermediate layer. That is, in order to obtain a large MR change rate, it is necessary that the Fermi levels of the intermediate layer, the magnetization fixed layer, and the magnetization free layer are substantially the same level. In the paramagnetic conductive layer 56 of the intermediate layer 51 according to the embodiment of the present invention, the Fermi level of the composite oxide is quite close to the Fermi level of Cu and the electron density of states is high, so that the MR change rate is sufficiently large. Can be realized.

Next, a method for manufacturing the GMR element according to the embodiment of the present invention will be described with reference to process cross-sectional views shown in FIGS. Here, a case where an Rb _0.3 MoO ₃ composite oxide is used for the paramagnetic conductive layer 56 will be described.

  (A) First, as shown in FIG. 3, a buffer layer 72 such as tantalum (Ta) is formed on the surface of a substrate 70 such as silicon (Si) using a sputtering method, a vacuum deposition method, or the like, and a lower electrode such as Cu. A layer 74, an antiferromagnetic layer 76 such as MnPt, a magnetization pinned layer 52 such as CoFe, and a magnetic coupling blocking layer 54 such as Cu are sequentially stacked. The thickness of each layer is, for example, about 5 nm for the buffer layer 72, about 200 nm for the lower electrode layer 74, about 10 nm for the antiferromagnetic layer 76, about 3 nm for the magnetization pinned layer 52, and about 0 for the magnetic coupling blocking layer 54. .2 nm. Here, the buffer layer 72 formed on the surface of the substrate 70 is polycrystalline. As a result, each layer from the lower electrode layer 74 to the magnetic coupling blocking layer 54 is formed as a polycrystal epitaxially grown on the polycrystal of the buffer layer 72.

(B) Next, a paramagnetic conductive layer 56 is formed on the surface of the magnetic coupling blocking layer 54. First, for example, the substrate 70 is mounted in a film forming chamber of a laser sputtering apparatus using an argon fluoride (ArF) or fluorine (F ₂ ) gas excimer laser, and evacuated until the ultimate vacuum is 10 ⁻⁵ Pa or less. An Rb _0.3 MoO ₃ film is deposited on the surface of the magnetic coupling interruption layer 54 using a mixed target having a composition with a molar ratio of Rb: Mo: O = 0.3: 1: 3. The film formation rate of laser sputtering is, for example, 0.02 to 0.1 nm / second. Thereafter, the formed Rb _0.3 MoO ₃ film is subjected to crystallization treatment by ion beam irradiation as necessary. The ion beam irradiation conditions are appropriately selected as long as the formed Rb _0.3 MoO ₃ film is not significantly etched. For example, when an argon (Ar) ion beam is used, irradiation may be performed with an acceleration voltage of about 50 V and an input power of about 50 W. As ion species of the ion beam, a rare gas element such as xenon (Xe) or krypton (Kr) can be used in addition to Ar. By such a film forming process, a paramagnetic conductive layer 56 of Rb _0.3 MoO ₃ composite oxide having a thickness of about 0.8 nm is formed on the magnetic coupling blocking layer 54 as shown in FIG.

  (C) Next, as shown in FIG. 5, on the surface of the paramagnetic conductive layer 56, an interface adjustment layer 58 such as Cu and a magnetization free layer 60 such as CoFe are formed by using a sputtering method, a vacuum deposition method, or the like. Are sequentially stacked. The thickness of each layer is, for example, about 0.2 nm for the interface adjustment layer 58 and about 3 nm for the magnetization free layer 60 such as CoFe. In order to make the magnetic moment of the magnetization fixed layer 52 uniform, a heat treatment is performed at about 270 ° C. for about 10 hours in a state where a magnetic field of about 5 kOe (kiloelsted) is applied in the magnetization direction. Here, the intermediate layer 51 is formed by the paramagnetic conductive layer 56, the magnetic coupling blocking layer 54 and the interface adjustment layer 58 sandwiching the paramagnetic conductive layer 56. In addition, the magnetoresistive effect layer 50 is formed by the intermediate layer 51, the magnetization fixed layer 52 and the magnetization free layer 60 sandwiching the intermediate layer 51. A protective layer such as Ta may be provided on the surface of the magnetization free layer 60.

(D) Next, a part of the magnetoresistive effect layer 50 and the antiferromagnetic layer 76 is selectively removed using a resist mask by a photoetching technique or the like to leave a trapezoidal shape. The magnetization free layer 60 on the outermost surface of the magnetoresistive effect layer 50 is formed in a substantially circular shape having a diameter of 1 μm or less, for example, 70 nm, for example. Subsequently, for example, using a lift-off technique, as shown in FIG. 6, the insulating layer 62 such as Al ₂ O ₃ and the hard magnetic layer 64 such as CoPt, the trapezoidal magnetoresistive effect layer 50 and the anti-strong layer are formed by sputtering. A film is selectively formed on the side surface of the magnetic layer 76 and on the surface of the antiferromagnetic layer 76. The insulating layer 62 has a thickness of 10 nm or more so that tunnel injection between the hard magnetic layer 64 and the lower electrode layer 74 does not occur.

  (E) Thereafter, as shown in FIG. 7, the surface of the magnetization free layer 60, the insulating layer 62, and the hard magnetic layer 64 where the upper electrode layer 80 such as Cu is exposed is formed by using a sputtering method, a vacuum deposition method, or the like. A film is formed. In this manner, the GMR element according to the embodiment of the present invention is completed.

Here, the film thickness of each layer of the GMR element can be confirmed by the signal intensity of each element using fluorescent X-ray analysis. The orientation direction of the Rb _0.3 MoO ₃ composite oxide of the paramagnetic conductive layer 56 can be confirmed by X-ray diffraction (XRD) measurement or the like. For example, if the b-axis of the composite oxide is in the “010” orientation in which the b-axis is perpendicular to the stacking surface, XRD is incident from a direction parallel to the surface and XRD measurement is performed to obtain a diffraction angle 2θ of 9 °. Diffraction intensity peaks are observed at three locations of ˜11 °, 13 ° to 15 °, and 17 ° to 19 °. As a result of XRD measurement by making X-rays incident from the direction parallel to the surface of the paramagnetic conductive layer 56 shown in FIG. 4, the diffraction angle 2θ is 9.9 °, 14.6 ° as shown in FIG. , And 18.4 °, diffraction intensity peaks P1, P2, and P3 are measured, respectively. Therefore, it can be confirmed that the b-axis of the Rb _0.3 MoO ₃ composite oxide of the paramagnetic conductive layer 56 is oriented in a direction perpendicular to the laminated surface.

The degree of oxidation of the paramagnetic conductive layer 56 was determined by preparing a sample in which about 2 nm of ruthenium (Ru) metal was laminated as a protective film on the surface of the CuAlO ₂ composite oxide of the paramagnetic conductive layer 56 shown in FIG. This can be confirmed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). According to the analysis, Mo is almost all hexavalent ions Mo ⁶⁺ , and only pentavalent ions Mo ⁵⁺ are present. Further, Rb is all in the monovalent ion Rb ⁺ state, and Co and Fe in the magnetization pinned layer 52 are all only metals (zero valence).

  About the produced GMR element, MR change rate, sheet resistance RA, and S / N ratio are measured. In addition, if a test for inspecting the relationship between the voltage applied to the GMR element and the resistance value of the GMR element by gradually increasing the sense current flowing through the GMR element, a voltage at which the resistance value starts to decrease suddenly, a so-called break The down voltage can be measured.

For example, the temperature characteristic of the normalized resistance value of the GMR element using the Rb _0.3 MoO ₃ composite oxide as the paramagnetic conductive layer 56 shown in FIG. 1 is a low temperature region below room temperature (300 K) as shown in FIG. It becomes almost constant regardless of temperature. Here, the normalized resistance value is obtained by dividing the resistance value of the GMR element at each temperature by the resistance value at room temperature. FIG. 9 also shows temperature characteristics of normalized resistance values of a conventional CPP type GMR element using Cu instead of the paramagnetic conductive layer 56 and a TMR element using Al ₂ O ₃ as a comparative example. It is shown. In general, the electrical resistivity of the TMR element increases when the temperature is lowered, and the electrical resistivity of the conventional GMR element is conversely reduced. Thus, as compared with conventional GMR elements and TMR elements, the electrical resistivity of the GMR element using the Rb _0.3 MoO ₃ composite oxide as the paramagnetic conductive layer 56 has stable temperature characteristics.

Further, the table of FIG. 10 shows MR change rates, sheet resistance RA, breakdown of sample numbers 1 to 16 according to the embodiment of the present invention and GMR elements and TMR elements of sample numbers 17 to 22 according to the comparative example. The device characteristics such as voltage and S / N ratio are shown. MR change rate and sheet resistance RA of the GMR element (sample No. 1) using Rb _0.3 MoO ₃ composite oxide as the paramagnetic conductive layer 56 are as large as 17.5% and 540 Ωμm ² , respectively, and have practically sufficient characteristics. It has become. Also, the breakdown voltage is as high as 720 mV. In the comparative example (sample number 17) using only Cu as the intermediate layer, the MR change rate and the sheet resistance RA are respectively too low, 0.2% and 60 Ωμm ^2, and the breakdown voltage is also inferior, 110 mV. The S / N ratio is good for both Sample No. 1 and Sample No. 17. On the other hand, in the TMR element (sample number 18) using the Al ₂ O ₃ layer as a comparative example, the MR ratio and the breakdown voltage show excellent characteristics of 32% and 920 mV, respectively, but the sheet resistance RA is It is abnormally high at 27000 Ωμm ^2, and the S / N ratio is poor and is not suitable for practical use.

FIG. 10 shows the composite oxide of the paramagnetic conductive layer 56 with potassium molybdenum oxide (K _0.3 MoO ₃ ) as sample number 2, thallium molybdenum oxide (Tl _0.3 MoO ₃ ) as sample number ₃ , and sample number 4. Sodium vanadium oxide (Na _0.6 V ₂ O ₅ ), copper vanadium oxide (Cu _0.9 V ₂ O ₅ ) as sample number ₅ , copper vanadium oxide (Cu _2.2 V ₄ O ₁₁ ) as sample number 6, sample number 7 As rubidium barium molybdenum oxide (Rb _0.2 Ba _0.1 MoO ₃ ), sample number 8 as potassium barium molybdenum oxide (K _0.2 Ba _0.1 MoO ₃ ), sample number 9 as thallium barium molybdenum oxide (Tl _0.2 Ba _0.1 MoO ₃ ) , sodium strontium vanadium oxide as a sample No. _{10 (Na 0.4 Sr 0.2 V 2} O 5), sample No. 1 As copper magnesium vanadium oxide _{(Cu 0.8 Mg 0.1 V 2 O} 5), copper calcium vanadium oxide as a sample No. _{12 (Cu 2.0 Ca 0.1 V 4} O 11), sodium niobium oxide as a sample No. 13 (Na _0.6 Nb ₂ O ₅ ), copper niobium oxide (Cu _0.9 Nb ₂ O ₅ ) as sample number 14, sodium tungsten oxide (Na _0.6 WO ₃ ) as sample number 15, and copper tungsten oxide (Cu _0.9 WO ₃ ) as sample number 16 Element characteristics of GMR elements using sample numbers 2 to 16 are shown. In FIG. 10, instead of the paramagnetic conductive layer 56, a sample number 19 is a TMR element using magnesium oxide (MgO) as an insulating layer, and sample numbers 20 to 22 are tin oxide (SnO ₂ ) as a semiconductor. ), Element characteristics of a GMR element using lanthanum nickel oxide (LaNiO ₃ ) and cuprous oxide (CuO) are also shown as comparative examples.

As is apparent from the table of FIG. 10, all of the sample numbers 2 to 16 using the composite oxide according to the embodiment of the present invention as the paramagnetic conductive layer 56 of the intermediate layer 51 of the GMR element have an MR change rate of 16. .4～19.5%, sheet resistance RA has a large value in the same manner as 670～970Omegamyuemu ² and sample No. 1. It can also be seen that the breakdown voltage is sufficiently high at 740 to 940 mV. On the other hand, in the TMR element of Sample No. 19 using MgO instead of the paramagnetic conductive layer 56, both MR change rate and breakdown voltage are sufficiently large as 27% and 1080 mV, but the S / N ratio is poor and practical. It is a problem. Sample numbers 20 to 22 using SnO ₂ , LaNiO ₃ and CuO instead of the paramagnetic conductive layer 56 have a good S / N ratio and a sufficiently high breakdown voltage of 450 to 740 mV. However, since the Fermi level of the semiconductor material of SnO ₂ , LaNiO ₃ and CuO is greatly different from the Fermi level of the magnetization fixed layer or the magnetization free layer, the MR ratio is remarkably small at 0.4% or less. It can be seen that Sample Nos. 1 to 16 are generally superior in device characteristics as compared to Sample Nos. 17 to 22. As described above, according to the GMR element according to the embodiment of the present invention, it is possible to realize a good S / N ratio with a large MR change rate and to improve durability.

(Other embodiments)
Although the embodiments of the present invention have been described as described above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment of the present invention, a complex oxide having a monoclinic structure is used as the paramagnetic conductive layer 56, but the structure of the complex oxide is not limited. Even if it is another crystal structure, it is a paramagnetic material as long as it is a complex oxide having one-dimensional electrical conductivity and having approximately the same Fermi level as that of each of the magnetization pinned layer 52 and the magnetization free layer 60. Needless to say, the conductive layer 56 can be used.

In the embodiment of the present invention, a Si semiconductor substrate is used as the substrate 70. However, the substrate 70 is not limited to the Si semiconductor substrate, and of course, a ceramic substrate such as alumina titanium carbide (Al ₂ O ₃ —TiC) may be used.

  As described above, the present invention naturally includes various embodiments that are not described herein. Accordingly, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

1 is a schematic cross-sectional view of a magnetoresistive effect layer according to an embodiment of the present invention. It is a figure used for description of the complex oxide used for the paramagnetic conductive layer which concerns on embodiment of this invention. It is sectional process drawing (the 1) which shows an example of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is sectional process drawing (the 2) which shows an example of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is sectional process drawing (the 3) which shows an example of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is sectional process drawing (the 4) which shows an example of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is sectional process drawing (the 5) which shows an example of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is a figure which shows an example of the temperature characteristic of resistance of the giant magnetoresistive effect element which concerns on embodiment of this invention. It is a figure which shows an example of the X-ray-diffraction measurement result of the paramagnetic conductive layer which concerns on embodiment of this invention. It is a table | surface which shows the element characteristic of the giant magnetoresistive effect element based on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 Magnetoresistance effect layer 51 Intermediate | middle layer 52 Magnetization pinned layer 54 Magnetic coupling interruption | blocking layer 56 Paramagnetic conduction layer 58 Interface adjustment layer 60 Magnetization free layer 62 Insulating layer 64 Hard magnetic layer 70 Substrate 72 Buffer layer 74 Lower electrode layer 76 Antiferromagnetic Layer 80 Upper electrode layer

Claims (3)

M _xy A _y DO _3-z (where M is an element selected from group I elements and thallium of the periodic table, and A is a group II element) Element selected from the above, D is an element selected from Group VA elements and Group VIA elements, and x, y, and z are 0.1 ≦ x ≦ 1.4, 0 ≦ y ≦ 0, respectively. 5. A giant magnetoresistive element comprising a paramagnetic conductive layer having an oxide layer represented by 5 · x and 0 ≦ z ≦ 0.7.   2. The oxide layer according to claim 1, wherein the oxide layer includes a monoclinic crystal structure, and one crystal axis direction is in a stacking direction of the magnetization pinned layer, the paramagnetic conductive layer, and the magnetization free layer. Giant magnetoresistive element. 3. The giant magnetoresistive element according to claim 2, wherein M _xy A _{y of the} oxide layer is continuous in a one-dimensional chain shape in the one crystal axis direction.

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