STUDY OF THE PHASE TRANSITION BY THE MAGNETOSTRICTION MEASUREMENT UNDER A PULSED HIGH MAGNETIC FIELD

脉冲强磁场下磁致伸缩测量相变的研究

基本信息

批准号：
06640477
负责人：
TAKEUCHI Tetsuya
金额：
$ 1.34万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640477/
关键词：
MAGNETOSTRICTION PULSED HIGH MAGNETIC FIELD CAPACITANCE METHOD THERMAL EXPANSION HEAVY FERMION KONDO EFFECT QUADRUPOLE 強磁場

项目摘要

The aim of this research project is to study the phase transition by the magnetstriction measurement under a pulsed high magnetic field. The principle of the measurement is the high sensitive three terminal method. For the test measurement, we constructed the magnetostriction cryostat for the measurement in a static magnetic field up to 8 T and thermal expansion cryostat. The temperature range is 1.8 K to 300 K.The system for the pulse field is under construction. Here we report the several results which has been obtained from the static field measurements.1.Antiferromagnetic transition and volume effect in Ce(Ru_<1-x>Rh_x)_2Si_2This compound has an antiferromagnetic ordering at 5.5 K and shows metamagnetic transitions at 3.5 and 6 T.From the neutron scattering measurements, it has been found that this antiferromagnetic ordering is the SDW transition having the magnetic wave vector along the c-axis. Electrical resistivity along the c-axis shows a large bump (about 30%) below the Neel t … More emperature, while in the a-axis, however, resistivity decreases as T^2 law with decreasing the temperature. From these results, it is concluded that the SDW transition is caused by the nesting effect of a part of Fermi surface along the c-axis. The anisotropic gap opens by the SDW transition. The thermal expansion shows a rapid decrease of the lattice constant below 50 K where the Kondo effect takes place. Below the Neel temperature, however, the rapid decrease of the lattice constant desappears and the lattice constant becomes almost constant. This result may imply that the INVAR and/or anti-INVAR effect due to the moment-volume instability does exist in 4f heavy electron systems.Magnetostriction in the SDW phase ia very small as the nomal metal. Above the critical field where the SDW is quenched, the unit cell volume rapidly increases with increasing the magnetic field. This large magnetostriction is characteristic for the heavy fermion compounds and indicates that the Kondo fluctuation still remains above the critical field.2.Anisotropic thermal expansion and field-induced structural phase transition in PrCu_2Thermal expansion in PrCu_2 is very anisotropic due to the highly anisotropic crystalline electric field. The metamagnetic transition is caused by a large modification of the crystalline electric field coming from a field induced structural phase transition. This structural phase transition probably come from the quadrupole-quadrupole interactions. Less

该研究项目的目的是在脉冲高磁场下研究磁铁测量的相变。测量的原理是高灵敏的三个末端方法。对于测试测量，我们构建了磁结构低温恒温器，用于在高达8 t的静态磁场和热膨胀低温恒温器中进行测量。温度范围为1.8 K至300K。脉冲场的系统正在建设中。在这里，我们报告了从静态现场测量中获得的几个结果。1。抗铁磁过渡和体积效应（ru_ <1-x> rh_x）_2SI_2SI_2 THINS AMPIOND在5.5 k处具有抗铁磁序，并在3.5和6 T. from中显示了元磁过渡，并在3.5和6 t. t.from中均散布了零散的分散量。具有沿C轴的磁波矢量的SDW过渡。沿C轴的电阻率显示出较大的凸起（约30％），低于Neel T…更多的紧急情况，而在A轴上，耐药性会随着温度降低而降低，因为T^2定律。从这些结果得出的结论是，SDW转变是由沿C轴一部分表面的嵌套作用引起的。各向异性间隙通过SDW过渡打开。热膨胀显示晶格常数在50 K以下的迅速下降。然而，低于Neel温度，晶格常数去皮的迅速下降和晶格常数几乎变为恒定。该结果可能表明，由于矩量不稳定确实存在于4F重电子系统中。在淬灭SDW的临界场的上方，随着磁场的增加，单位细胞体积迅速增加。这种大型磁截图是重型费米化合物的特征，并表明近相波的波动仍然保持在关键场上。2.Anisotropic热膨胀和PRCU_2中PRCU_2中PRCU_2中的结构相变的结构相变，由于极度偏型，由于高度偏型型偏角。元磁过渡是由来自磁场引起的结构相变的晶体电场的大规模修饰引起的。这种结构相过渡可能来自四极极端相互作用。较少的