JP2006099864A - Magnetic information reproducing apparatus and magnetic transfer element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic information reproducing apparatus which reproduces non-destructively and with high sensitivity the information recorded on various magnetic recording media and a magnetic transfer element. <P>SOLUTION: The magnetic information reproducing apparatus is constituted of; a magnetic recording medium 11, where information is recorded; a magnetic transfer element 12 which transfers the magnetization state of a magnetic recording medium 11; a light source system 20 which irradiates the magnetic transfer element 12 with a beam of linear polarization; a reproducing system 30 which reproduces information from the beam which is polarized by the magnetic transfer element 12; and a tracking direction detecting system 40, which detects the direction of the tracks. A magnetization state is detected, by scanning the beam with a polarizer 23 on the surface of the magnetic transfer element 12, a deviation angle of a scanning direction and track direction is detected by a track direction detecting system 40, and the scanning direction is made to coincide with the tracking direction by a scan control section 26. Iron atoms of a magnetic garnet film of magnetic transfer element is replaced by an In atom, and successful transfer is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic information reproducing apparatus and a magnetic transfer element for reproducing information recorded on magnetic recording media such as various magnetic tapes and disks.

  A magnetic recording medium has features such as a large capacity, non-volatility of recorded information, long-term reliability, and low cost as compared with a semiconductor memory, and a recording / reproducing apparatus using the magnetic recording medium has a magnetic capacity of a large computer system. It is widely used for business purposes such as a disk device, a magnetic tape device for backup and a video device for broadcasting, and a consumer use such as a video device at home and a music recording / playback device.

  In general, in a video apparatus, an audio signal travels in a longitudinal direction on a magnetic tape and is recorded by a stationary head, thereby forming a track parallel to the longitudinal direction of the magnetic tape. On the other hand, the image signal is recorded by being inclined with respect to the longitudinal direction of the magnetic tape by a magnetic head attached to a rotating cylinder, and a track is formed obliquely with respect to the longitudinal direction of the magnetic tape.

  On the other hand, in order to reproduce the recorded magnetic information, the magnetic recording head accurately scans the track recorded on the magnetic tape, detects the magnetic field leaking from the magnetic tape, and converts it to voltage or current. Magnetic information is reproduced.

In the video apparatus, various recording formats are used as the recording density is increased and the apparatus is downsized. These recording formats are usually not compatible with each other, and a dedicated video device is required for each recording format for reproduction.
Nomura, Tokumaru “Magnetic read-out using magnetic garnet film” IEICE Transactions Vol. J67-C No. 11 p. 871 (1984)

  However, it is difficult to maintain a dedicated video device for each recording format for several decades in terms of technical and maintenance parts.

  Also, magnetic tape on which valuable information is recorded needs to be dubbed to convert the recording format every time the recording format of the video apparatus is changed. There is a problem that it is very expensive to keep working.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic information reproducing apparatus and a magnetic transfer element for reproducing information recorded on various magnetic recording media in a non-destructive manner with high sensitivity. Is to provide.

  According to one aspect of the present invention, a magnetic recording medium having a track on which information is recorded, and a magnetic having a transfer track that is disposed in proximity to the magnetic recording medium and is magnetically formed corresponding to the track. A transfer element, a scanning means for irradiating the magnetic transfer element with a light beam, scanning the light beam, a reproducing means for reading information by the light beam reflected from the magnetic transfer element, and the magnetic transfer element are reflected. A track longitudinal direction detecting means for detecting a deviation between the scanning direction of the light beam and the longitudinal direction of the transfer track based on the measured light beam, and scanning based on a signal corresponding to the deviation supplied from the track longitudinal direction detecting means. There is provided a magnetic information reproducing apparatus comprising a scanning control unit for controlling the scanning direction of the means.

  According to the present invention, a track on which information on a magnetic recording medium is recorded is transferred to a magnetic transfer element, and a longitudinal direction of a magnetically formed transfer track is detected by scanning a beam. By scanning and reproducing the beam along the transfer track thus detected, the information recorded on the track of the magnetic recording medium having various formats can be reliably reproduced.

According to another aspect of the present invention, a magnetic garnet film is provided that is disposed close to a magnetic recording medium having a magnetization state corresponding to recorded information and is magnetized corresponding to the magnetization state. The magnetic garnet film is made of A ₃ B ₅ O ₁₂ (A is an atom of a rare earth element site, and B is an atom of a site containing an iron element). Wherein A contains Bi atoms of 0.2 or more and 1.0 or less, and B contains In atoms of 0.2 or more and 1.2 or less per molecule. A magnetic transfer element is provided.

  According to the present invention, by setting the composition of the magnetic garnet film as described above, the information recorded on the magnetic recording medium can be reliably transferred, the Faraday rotation angle can be increased, and the S / N ratio can be improved. A magnetic transfer element can be realized.

  According to the present invention, information recorded on a track of a magnetic recording medium having various formats is obtained by scanning and detecting a beam in the longitudinal direction of the transfer track and scanning and reproducing the beam along the transfer track. Can be played reliably.

  Embodiments will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a magnetic information reproducing apparatus according to an embodiment of the present invention. Referring to FIG. 1, a magnetic information reproducing apparatus 10 according to the present embodiment includes a magnetic recording medium 11 on which information is recorded, a magnetic transfer element 12 that transfers a magnetization state of the magnetic recording medium 11, and a magnetic transfer element 12. A light source system 20 for irradiating a linearly polarized beam, a reproducing system 30 for reproducing information from the beam reflected by the magnetic transfer element 12, a track direction detecting system 40 for detecting the track direction, and the like. In FIG. 1, a medium driving system for moving the magnetic recording medium 11 is omitted. Here, a magnetic tape will be described as an example of the magnetic recording medium 11, and the same reference numeral as that of the magnetic recording medium 11 is given.

  The magnetic information reproducing apparatus 10 magnetically transfers information recorded on the magnetic tape 11 to the magnetic transfer element 12 and irradiates the magnetic transfer element 12 with a beam, thereby using the Faraday effect to transfer the transferred information. It is to detect.

  The light source system 20 includes a light source 21, a polarizer 22 that converts a beam emitted from the light source 21 into linearly polarized light, and directions of two axes that are perpendicular to each other in a plane perpendicular to the traveling direction of the beam direction. And a beam splitter 25 that transmits a linearly polarized beam and makes light reflected from the magnetic transfer element 12 enter the reproducing system 30 or the like.

  The light source 21 is not particularly limited, and any one of ultraviolet light, visible light, and infrared light may be used. For the light source 21, for example, a laser is preferable in terms of directivity, and is particularly small and has low power consumption. In this respect, a semiconductor laser is preferable. The light source 21 preferably emits a linearly polarized beam.

  The polarizer 22 is made of, for example, a polarizing prism or a polaroid using dichroism, and converts the light into linearly polarized light when the light source is natural light. When the light source 21 emits a linearly polarized beam, the polarizer 22 may not be provided.

  The deflector 23 includes two uniaxial deflecting units (not shown) arranged in series that deflect the traveling direction of the beam on a plane (XY plane) perpendicular to the incident direction (Z direction) of the beam. The deflection directions of the uniaxial deflection units are set in directions orthogonal to each other. For example, one uniaxial deflection unit is in the X direction (corresponding to the width direction of the magnetic tape 14), and the other uniaxial deflection unit is in the Y direction (magnetic). Corresponding to the longitudinal direction of the tape 14). In this way, by arranging the uniaxial deflecting units whose deflection directions are perpendicular to each other in series, the beam can be deflected in any direction on the XY plane. As a result, the beam can be directed in any direction on the magnetic transfer element 12. Can be scanned. Note that the deflection directions of the two uniaxial deflecting portions do not necessarily have to be orthogonal to each other, and the angle is not limited unless they are set parallel to each other.

  Specifically, the deflector 23 includes an acousto-optic element and a galvanometer, and the uniaxial deflecting unit is constituted by one acousto-optic element and a galvanometer mirror, which are arranged in series. A signal corresponding to the polarization angle is supplied from each scanning control unit 26 to each uniaxial deflection unit, and the deflection direction and the deflection speed are controlled. When the uniaxial deflecting unit is an acousto-optic device, for example, the supplied signal has a polarization angle determined according to, for example, a voltage value. Specifically, the signal is voltage-frequency converted to correspond to the frequency. Thus, the angle of the wave front of the phonon standing wave generated in the single crystal in the acousto-optic device is determined, and the beam is deflected by the wave front to determine the deflection angle. The acousto-optic device is preferable in that it can be easily downsized. As will be described later, a signal corresponding to the deviation angle between the beam scanning direction and the track direction is supplied to the scanning control unit 26, and a voltage signal corresponding to the scanning direction is supplied to each of the two uniaxial deflecting units according to the signal. Is supplied. The beam emitted from the polarizer 23 is set to have a constant deflection angular velocity when scanning the magnetization state of the magnetic transfer element with respect to the beam incident on the polarizer 23.

  The fθ lens 24 converts the beam having a constant deflection angular velocity deflected by the deflector 23 into a constant velocity beam. That is, the fθ lens 24 keeps the scanning speed of the beam that scans the surface of the magnetic transfer element 12 constant. By doing so, it becomes easy to synchronize with the clock when information is processed by the demodulation circuit in the reproduction system, and phase shift can be suppressed.

  The beam splitter 28 is not particularly limited, and may be a plate type or a cube type. The linearly polarized beam passes through the beam splitter 28 and is irradiated on the surface of the magnetic transfer element 12.

  FIG. 2 is an enlarged cross-sectional view of the magnetic transfer element and the magnetic tape. Referring to FIG. 2 together with FIG. 1, the magnetic transfer element 12 has a magnetic garnet film 15 formed on the surface of a substrate 16, and a magnetic layer 14 is formed on the base film 13 on the magnetic garnet film 15 side. The magnetic tape 11 is arranged so as to face the magnetic layer 14 side. A leakage magnetic field Hex generated by the magnetization 14 m recorded on the magnetic tape 11 is applied to the magnetic garnet film 15 and magnetized in a direction perpendicular to the surface of the substrate 16. Then, the linearly polarized beam irradiated from the substrate 16 side passes through the magnetic garnet film 15, is reflected by the surface 15a, and passes through the magnetic garnet film 15 again. When the beam passes through the magnetic garnet film 15 twice, the Faraday rotation angle is doubled and reproduction with a high S / N ratio can be performed.

  Note that a metal reflective film made of Al or Cr may be provided on the surface 15 a of the magnetic garnet film 15. The reflectivity of the beam is improved, the S / N ratio can be further improved, and it also functions as a protective film for the magnetic garnet film. Further, a protective film made of a material having a hardness similar to or higher than that of the abrasive contained in the magnetic tape or the magnetic tape protective film may be provided on the surface of the magnetic garnet film or the surface of the reflective film. Examples of the protective film include a hydrogenated carbon film (diamond-like carbon film) and a SiC film.

The magnetic garnet film 15 has ferrimagnetism and has a composition represented by A ₃ B ₅ O ₁₂ (A is an atom of a rare earth element site and B is an atom of a site containing an iron element).

The inventors of the present application have eagerly searched for a composition of a magnetic garnet film capable of reliably transferring information recorded on a magnetic tape or a flexible disk, and have found the following composition. That is, the Faraday rotation angle can be increased by adding A to the composition of A ₃ B ₅ O ₁₂ so that A contains Bi atoms in an amount of 0.2 to 1.0. When Bi atoms are less than 0.2, the Faraday rotation angle is lowered.

  At the same time, the saturation magnetization can be increased by adding B to 0.2 to 1.2 in atoms per molecule. When the In atom exceeds 1.2, the saturation magnetization is remarkably lowered, and when it is 1.3 or more, the saturation magnetization is lowered as compared with the case where no In atom is contained.

  By setting the magnetic garnet film 15 to such a composition, the saturation magnetization increases, so that the sensitivity of magnetic transfer is improved. Furthermore, since the Faraday rotation angle is large, the transferred information can be reproduced with a good S / N ratio.

Furthermore, by setting the composition of A ₃ B ₅ O _{12 so} that Ga atoms per molecule are 0.1 or more and 2.0 or less, the coercive force of the magnetic garnet film 15 can be reduced and the residual magnetization Even with a small magnetic tape 11 or a magnetic tape 11 with a high linear recording density and a small leakage magnetic field, the recorded information can be easily transferred and reproduction with a good S / N ratio is possible.

  The thickness of the magnetic garnet film 15 is preferably set to 0.5 μm to 10 μm from the viewpoint of a good transfer state. The magnetic garnet film 15 preferably has a coercive force set to 100 Oe (7.9 kA / m) or less. Transfer is possible even when the leakage magnetic field is small.

As the substrate 16, a nonmagnetic substrate capable of epitaxially growing the magnetic garnet film 15 is selected and is preferably a nonmagnetic substrate having a garnet structure. For example, Gd ₃ Ga ₅ O ₁₂ , (GdGa) ₃ (ZrMgGa) ₅ O ₁₂ , Nd ₃ Ga ₅ O ₁₂ , (GdCa) ₃ (ZrMgGa) ₅ O ₁₂ is preferably used for the substrate 16.

  The reproduction system 30 includes an analyzer 31, a half mirror 32 that reflects and transmits the beam to the track direction detection system 40 and branches the beam, and a condensing lens 33 that collects the beam transmitted through the half mirror 32, A photo detector 34 for detecting the light intensity of the collected beam, an amplifier 35 for amplifying the signal from the photo detector 34, and a signal processing circuit 36 comprising a demodulation circuit for extracting information from the amplified signal, etc. Is done.

  A known optical component can be used as the optical component constituting the reproduction system 30. For example, the analyzer 31 is appropriately set so that the deflection surface is at an angle with a good S / N ratio with respect to the polarizer 22. The half mirror 32 may use the beam splitter 25 described above. As the photodetector 34, a known photodetector such as a photodiode can be used, and a two-divided photodiode may be used for the convenience of adjusting the condensing position.

  The track direction detection system 40 includes an image sensor 41 that receives the beam reflected by the half mirror 32, an amplifier 42 that amplifies the signal from the image sensor 41, and a deviation angle between the scanning direction and the track direction from the amplified signal. And a track direction detection unit 43 that supplies a deviation angle signal corresponding to the deviation angle to the scanning control unit 26.

  The image sensor 41 is a two-dimensional image sensor, for example, a CCD sensor, and can image the magnetization state in which the scanned beam is transferred to the magnetic garnet film 15 of the magnetic transfer element 12 by the image sensor 41.

  FIG. 3 is a microscopic image showing the magnetization state of the magnetic garnet film of the magnetic transfer element 12. FIG. 3 shows an observation of the magnetization state of the magnetic garnet film, in which the magnetic transfer element 12 and the video tape are brought into contact with each other and the magnetization state of the audio track is transferred by using a video tape as the magnetic tape, with a polarizing microscope.

  Referring to FIG. 3, it can be confirmed that the magnetic garnet film reflects the magnetization state of the audio track, and light and shade are generated according to the direction of magnetization. The image sensor 41 can image such a magnetization state of the magnetic garnet film.

  The track direction detection unit 43 detects whether a beam is scanning within one track based on a signal from the image sensor 41, and further detects a deviation between the track direction and the scanning direction.

  FIG. 4 is a schematic diagram for explaining the relationship between the scanning direction of the light beam and the track direction. FIG. 4 shows a track 19 transferred to the magnetic transfer element 12 corresponding to the track 18 magnetically recorded on the magnetic tape 11. The beam scanning direction is Dsc, and the magnetic tape traveling direction is Dtp.

  Referring to FIG. 4, the track 19 transferred to the magnetic transfer element 12 is formed in substantially the same manner as the track 18 recorded on the magnetic tape, and a beam spot is scanned along the track 19. For example, when the beam is not scanned from the track 19 and a region corresponding to the guard band between the tracks 19 is scanned, the rotation angle of the change surface of the reflected beam is not changed, and the image sensor is as shown in FIG. The strength of strength is lost. Thus, it can be determined whether or not scanning is performed along the track direction. Further, for example, the deviation between the track direction and the scanning direction, for example, the deviation angle formed by both directions can be detected from the position where the signal corresponding to the guard band appears from the start position of the track 19.

  The scanning control unit 26 sets the scanning direction by adjusting the speed at which the deflection angles of the two uniaxial deflection units of the deflector 23 described above are changed.

  The deflector 23 scans the beam from the start position of the track to the end position of the track in a predetermined direction, for example, a direction corresponding to the track direction of the magnetic tape 11, and sets the intensity of the beam to almost 0, thereby starting the next track. Then, the beam intensity is set to a predetermined intensity again and scanning is performed in the same manner.

  Next, a method for reproducing information on a magnetic tape using the magnetic information reproducing apparatus 10 will be described with reference to FIGS. FIG. 5 is a flowchart showing the reproducing method.

  First, the magnetic tape 11 having an unknown format was moved at a predetermined moving speed, and the beam was scanned by the polarizer 23 in an arbitrary direction, for example, the longitudinal direction of the magnetic tape 11, and formed on the magnetic transfer element 12. The direction of the transfer track is detected (S102). The scanning range is, for example, a range narrower than the length of the magnetic transfer element 12 (the length in the same direction as the longitudinal direction of the magnetic tape), and the beam reflected by the magnetic transfer element 12 is repeatedly scanned and the image sensor 41 is scanned. The track direction detector 43 detects the deviation between the scanning direction and the transfer track direction.

  Next, it is determined whether or not the deviation of the scanning direction from the longitudinal direction of the transfer track is larger than a predetermined amount, that is, whether or not the beam deviates from the transfer track (S104). When the deviation is larger than the predetermined amount, a signal corresponding to the deviation is supplied to the scanning control unit 26 to the scanning control unit 26. The scanning control unit 26 performs adjustment to match the scanning direction of the polarizer 23 with the longitudinal direction of the transfer track in accordance with the signal (S106).

  When the deviation between the scanning direction and the track direction is within a predetermined amount (S104), the scanning timing of the beam is synchronized so as to scan from the start position to the end position of the transfer track (S108). The start position may be determined from the image of the magnetization state obtained by the image sensor 41, or may be determined by detecting an address mark or the like indicating the start position by the reproduction system 30. The end position is similarly determined.

  Next, the information recorded for each track by the reproduction system 30 is reproduced by a normal method (S110). As described above, information on the magnetic tape recorded in an unknown format can be reproduced.

  When the track is formed parallel to the longitudinal direction of the magnetic tape 11, for example, when the audio signal of the video tape or the serpentine format is used, the beam is not scanned in the reproduction (S110). The beam is fixed to the desired track.

  According to the present embodiment, the track on which information on the magnetic tape 11 is recorded is transferred to the magnetic transfer element 12 as a magnetic transfer track. The beam is scanned in the longitudinal direction of the transfer track by the polarizer 23, the longitudinal direction of the transfer track is detected by the track direction detection unit 43, and the scanning direction and the scanning speed are controlled by the scanning control unit 26, and the beam is moved along the transfer track. The information recorded on the track of the magnetic tape 11 having various formats can be surely reproduced.

[Example]
Next, magnetic garnet films of the magnetic transfer element were formed with different compositions. The magnetic garnet film was formed using a liquid phase epitaxial method. The magnetic garnet film thus formed was cut into a size of 5 mm × 5 mm together with a non-magnetic substrate using a diamond cutter to obtain a magnetic transfer element. The magnetic transfer element thus formed is placed in contact with a magnetic tape (coercive force 740 Oe (58.5 kA / m), residual magnetic flux density 1100 Gauss (0.11 T)) on which a television signal is recorded, and polarized. It was examined whether the magnetization of the magnetic tape was transferred to the magnetic garnet film using a microscope. Note that “◯” indicates that an image of a good magnetization state is observed, and “x” indicates that the magnetization state is missing or cannot be confirmed.

  FIG. 6 is a diagram showing the characteristics of the magnetic garnet film of the magnetic transfer element. The composition of the magnetic garnet film in FIG. 6 shows the composition of the site containing the rare earth element in the portion enclosed in parentheses “{}”, and the portion enclosed in the parentheses “[]” is the site containing the iron element. The composition is shown.

  Referring to FIG. 6, it can be seen that the magnetic garnet films of sample numbers 1 to 4 have a good transfer state with respect to sample numbers 5 and 6. Sample Nos. 1 to 4 have a coercive force of 7.9 kA / m or less, the saturation magnetization increases due to the addition of In to the site containing the iron element, and the transfer state is improved because the efficiency of magnetic transfer is improved. It is good.

  The magnetic garnet film may be formed by RF sputtering or laser ablation.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims. It can be changed.

  For example, in the above-described embodiment, the magnetic tape has been described as an example of the magnetic recording medium. However, the present invention can be applied to a flexible disk or a hard disk having a magnetic layer of a metal thin film. Further, it is apparent that the present invention can be applied not only to the in-plane recording type magnetic recording medium but also to the perpendicular recording type magnetic recording medium from the transfer mechanism shown in FIG.

It is a block diagram of the magnetic information reproducing | regenerating apparatus which concerns on embodiment of this invention. It is an expanded sectional view of a magnetic transfer element and a magnetic tape. It is a microscope image which shows the magnetization state of the magnetic garnet film | membrane of a magnetic transfer element. It is a schematic diagram for demonstrating the relationship between the scanning direction of a light beam, and a track direction. It is a flowchart which shows the reproduction | regeneration method. It is a figure which shows the characteristic of the magnetic garnet film | membrane of a magnetic transfer element.

Explanation of symbols

10 Magnetic Information Reproducing Device 11 Magnetic Recording Medium (Magnetic Tape)
DESCRIPTION OF SYMBOLS 12 Magnetic transfer element 13 Base film 14 Magnetic layer 15 Magnetic garnet film 16 Board | substrate 18, 19 Track 20 Light source system 21 Light source 22 Polarizer 23 Deflector 24 f (theta) lens 25 Beam splitter 26 Scan control part 30 Reproduction | regeneration system 31 Analyzer 32 Half mirror 33 Condensing Lens 34 Photodetector 35 Amplifier 36 Signal Processing Circuit 40 Track Direction Detection System 41 Image Sensor 42 Amplifier 43 Track Direction Detection Unit

Claims (9)

A magnetic recording medium having a track on which information is recorded;
A magnetic transfer element having a transfer track disposed close to the magnetic recording medium and magnetically formed corresponding to the track;
Scanning means for irradiating the magnetic transfer element with a light beam and scanning the light beam;
Track length for detecting a deviation between the scanning direction of the light beam and the longitudinal direction of the transfer track based on the reproducing means for reading information by the light beam reflected from the magnetic transfer element and the light beam reflected from the magnetic transfer element. Direction detection means;
And a scanning control unit for controlling a scanning direction of the scanning unit based on a signal corresponding to the deviation supplied from the track longitudinal direction detection unit. The magnetic transfer element has a magnetic garnet film having a composition represented by A ₃ B ₅ O ₁₂ (A is an atom of a rare earth element site and B is an atom of a site containing an iron element),
2. The magnetic garnet film according to claim 1, wherein A contains Bi atoms of 0.2 or more and 1.0 or less, and B contains In atoms of 0.2 or more and 1.2 or less per molecule. The magnetic information reproducing apparatus described. The magnetic recording medium is a magnetic tape;
3. The magnetic information reproducing apparatus according to claim 1, wherein the magnetic transfer element is arranged so as to face the magnetic tape and substantially cover a region in the width direction of the magnetic tape.   The magnetic information according to claim 1, wherein the scanning unit includes a deflector that scans in a two-dimensional direction in a plane perpendicular to the incident direction of the light beam. Playback device.   5. The magnetic information according to claim 4, wherein the deflector includes two uniaxial deflecting portions each having a uniaxial deflection direction, and is arranged so that the deflection directions are orthogonal to each other in the vertical plane. Playback device.   6. The magnetic information reproducing apparatus according to claim 5, wherein the uniaxial polarization unit is composed of an acousto-optic element or a galvanometer mirror.   The magnetic information reproducing apparatus according to claim 4, wherein the scanning unit includes an fθ lens on an exit side of the deflector. A magnetic garnet film disposed adjacent to a magnetic recording medium having a magnetization state corresponding to recorded information and magnetized corresponding to the magnetization state, and optically detecting the magnetization state of the magnetic garnet film A transfer element,
The magnetic garnet film has a composition represented by A ₃ B ₅ O ₁₂ (A is an atom of a rare earth element site and B is an atom of a site containing an iron element),
A magnetic transfer element, wherein A contains Bi atoms of 0.2 to 1.0 and B contains In atoms of 0.2 to 1.2 per molecule.   9. The magnetic transfer element according to claim 8, wherein the magnetic garnet film contains 0.1 to 2.0 Ga atoms per molecule in B.