2004 Fiscal Year Final Research Report Summary
Observation of fine domain configuration by detecting micro-Hall effect under scanning probe microscopy
| Project/Area Number |
15360160
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NAKAGAWA Shigeki Tokyo Institute of Technology, Dept.of Physical Electronics, Associate Professor, 大学院・理工学研究科, 助教授 (60180246)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Ferromagnetic Hall effect / Anomalous Hall effect / Perpendicular Magnetic Recording Media / Scanning Probe Microscopy / Magnetization state / Magnetization Process / Double layered media |
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| Research Abstract |
The effects of magnetic interaction between the recording layer and soft magnetic underlayer were evaluated for an FePt/FeCoB (or NiFe) double-layered thin films. Presence or absence of a non-magnetic intermediate layer between the recording layer and the soft magnetic underlayer revealed significantly different results in the Hall voltage measurement indicating the interlayer magnetic interactions. Especially in the FePt/FeCoB system the effects were remarkable. Existence of a very thin layer of FeCoB thin film adjacent to the FePt layer was found to have significant effect in the magnetization process of the FePt layer due to the strong exchange interaction between them. On the other hand, soft magnetic properties of the FeCoB or the NiFe layer was found to deteriorate due to the disturbance in the in-plane magnetization orientation by the fringing flux from the FePt layer. Deterioration of the soft magnetic properties was found to be in the largest extent when the FePt layer was in AC erased state. The reason can be attributed to the increased fluctuation in the fringing field to the soft magnetic layer. Moreover, compared to the FeCoB,NiFe thin films coexisting with an FePt layer were found more vulnerable to the fringing field. Since the Hall effect is a phenomenon intrinsic to the material in concern, it is not always possible to detect satisfactory results. For some cases factors such as the specimen composition and the physical structure seem to dominate the exertion of the Hall voltage. However, for most of the materials studied so far for the application of high-density magnetic recording media or memory devices, application of spin dependent Hall effects is thought to be suitable not only for evaluation but for the fabrication of new devices also. Based on the results found in this study further intelligent applications of the Hall effects are highly expected.
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