2022 Fiscal Year Final Research Report
The highly sensitive magneto-optic measurement system for the surface magnetization of permanent magnets with a Sagnac interferometer
| Project/Area Number |
20K04498
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Multi-year Fund |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 21030:Measurement engineering-related
|
|---|
| Research Institution | Yamagata University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2020-04-01 – 2023-03-31
|
| Keywords | 磁気光学カー効果 / 磁気光学ファラデー効果 / 永久磁石 / 磁性薄膜 / サニャック型干渉計 |
|---|
| Outline of Final Research Achievements |
We demonstrated the Faraday rotation angle measurements with a standard sample (TGG), applying a small magnetic field (< 10 G). (Faraday angle is 1 mrad when 3.2 G is applied, estimated from the Verdet's constant of the sample.) The precision of angle reached 0.1 mrad in the short time measurements, but we encountered the drift of the order of 1 mrad in the long time (>10 min.) magnetization curve measurements. The close inspection shows that the interference between the main beam and the residual reflection from the objective lens is the source of fluctuations. (The intensity of interference is unstable due to the path lengths changes of the two lights) It is necessary to use the light source with a short optical coherence length, such as super luminescent diode, to suppress the noise.
|
| Free Research Field |
磁性物理学
|
| Academic Significance and Societal Importance of the Research Achievements |
永久磁石はスピーカー、ハードディスクドライブ、汎用モーター等広く使われており、特に急速に普及することが予想される電動自動車のパワーユニットの主要部品としてその性能向上が急務となっている。本研究は永久磁石材料開発の初期段階において薄膜状の結晶を作製し、その基本的な磁気特性（磁化）を測定する際に必要となる磁気光学測定法の測定精度向上と、位置分解測定を目指した。精度向上のために通常使われている測定法とは異なる手法を試みて、この手法を使った測定における問題点を明らかにすることができた。
|
