1994 Fiscal Year Final Research Report Summary
Development of High-Sensitive Magnetic Measurement System under High Pressures
| Project/Area Number |
05640413
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
固体物性Ⅱ(磁性・金属・低温)
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
ISHIZUKA Mamoru Osaka Univ.Fac.of Engineering Science assistant, 基礎工学部, 助手 (30184542)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
AMAYA Kiichi Osaka Univ.Fac.of Engineering Science Professor, 基礎工学部, 教授 (80029503)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Keywords | High sensitive magnetic measurement / High pressure / Diamond anvil cell / Position differentiating detection / SQUID magnetometer |
|---|
| Research Abstract |
A precise magnetization measurement system for extremely small samples in the diamond anvil cell has been developed. The system is based on position differentiating detection (PDD) combined with the use of a SQUID magnetometer. The PDD is a kind of the VCM (Vibrating Coil Magnetometer) and is suitable for the case where high sensitivity detection is required for a sample around which there is little space for the detection coil. The present system enables us to make magnetization measurements at pressures up to about 12GPa in the temperature range from 1.4 to 30K.The sensitivity is about 10^<-9> to 10^<-10> emu. Three piezoelectric actuators of a bimorph type are used at liquid helium temperature for stable vibration of the detection coil with an amplitude of 90mum around the tips of the diamond anvils. One of the problems characteristic of the VCM system is how to reduce the contribution of the field from a magnet. A position sensing technique at low temperature has been developed so as to estimate the contribution of the magnetizing field because the gradient of the magnetic field in the magnet strongly depends on the position of the detection coil. Determination of position is made using two composite magnets and the detection coil as a position sensor. The performance of the system is illustrated by magnetization measurements of EuTe under high pressures. Pressure induced ferromagnetism of EuTe was observed for the first time at pressures of 7.9GPa and above.
|
