Current perpendicular-to-the-plane structure spin valve magnetoresistive head

• US 20020097538A1
• Filed: 03/29/2001
• Published: 07/25/2002
• Est. Priority Date: 11/16/2000
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Atsushi, Shimizu, Yutaka, Nagasaka, Keiichi, Seyama, Yoshihiko
• Granted Patent: US 6,781,799 B2
• Time in Patent Office: Days
• US Class Current: 360/324.11
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 5/00 Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor G11B11/00 and G11B13/00 take precedence
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]

Abstract

A current perpendicular-to-the-plane (CPP) structure spin valve magnetoresistive (MR) transducer includes an insulating layer. A pinned or free ferromagnetic layer serves to space or isolate the insulating layer from a non-magnetic spacer layer interposed between the pinned and free ferromagnetic layers. The sensing current is allowed to penetrate through the insulating layer. Fine pin-holes generally formed in the insulating layer are supposed to enable migration of electrons through the insulating layer. Similar to the situation in which the sensing current is allowed to flow through a reduced sectional area, a larger variation can be obtained in response to the inversion of the magnetization in the free ferromagnetic layer. The spin valve MR transducer is expected to greatly contribute to realization of a still higher recording density. Moreover, the spin valve MR transducer is also expected to exhibit an electric resistance approximately equal to a tenth part of that of a well-known tunnel junction magnetoresistive (TMR) element. Accordingly, a thermal noise can significantly be suppressed in the spin valve MR transducer as compared with the TMR element.

Claims

1. A current perpendicular-to-the-plane structure spin valve magnetoresistive transducer comprising:

a free ferromagnetic layer;

a non-magnetic spacer layer contacting the free ferromagnetic layer over a first interface;

a pinned ferromagnetic layer contacting the non-magnetic spacer layer over a second interface; and

an insulating layer spaced by the pinned ferromagnetic layer from the non-magnetic spacer layer.

2. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 1, wherein said insulating layer includes a compound consisting of at least elements of two kinds.

3. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 2, wherein said compound is an oxide.

4. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 1, wherein said insulating layer is interposed between a pair of said pinned ferromagnetic layer.

5. A current perpendicular-to-the-plane structure spin valve magnetoresistive transducer comprising:

a free ferromagnetic layer;

a non-magnetic spacer layer contacting the free ferromagnetic layer over a first interface;

a pinned ferromagnetic layer contacting the non-magnetic spacer layer over a second interface; and

an insulating layer spaced by the free ferromagnetic layer from the non-magnetic spacer layer.

6. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 5, wherein said insulating layer includes a compound consisting of at least elements of two kinds.

7. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 6, wherein said compound is an oxide.

8. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 5, wherein said insulating layer is interposed between a pair of said free ferromagnetic layer.

9. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 5, further comprising another insulating layer spaced by the pinned ferromagnetic layer from the non-magnetic spacer layer.

10. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 9, wherein said another insulating layer includes a compound consisting of at least elements of two kinds.

11. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 10, wherein said compound is an oxide.

12. The current perpendicular-to-the-plane structure spin valve magnetoresistive transducer according to claim 9, wherein said insulating layer is interposed between a pair of said pinned ferromagnetic layer.