Magneto-Acoustic Effect of the Heavy Fermion Compound by Giga-Hertz Ultrasonic Measurement

本文利用超声测量方法研究了稀土化合物中的电子-应变相互作用，特别是重费米子和价态涨落体系。本研究建立了一种基于单差检波及其相位比较器的超声波检测系统，可检测频率高达1GHz的高频超声波信号。为实现稀释制冷机的低温测量，研制了频率高达1GHz的同轴空气管路和低温放大器。并设计了螺旋齿轮和两圆测角仪等多种样品定向装置。在声学de Haas-van Alphen测量中，我们重点研究了各种重费米子化合物。特别是我们成功地观察到了CeSb中的重空穴态。这一结果为Kasuya等人提出的CeSb中的p-f混合机制提供了必要的证据，而所观察到的大的振荡强度是由于空穴态态密度的显著增强。声学dHvA效应和振荡磁致伸缩实验可以为重费米子和超导化合物中电子-应变相互作用的异常性质提供丰富的信息。无论如何，还需要对超声方法进行进一步的持续研究。

Employing the ultrasonic measurements, we have investigated the electron-strain interaction of the rare earth compounds, in particular the heavy Fermion and valence fluctuation systems. In the present research we constructed a new ultrasonic system based on the monodyne detection and its phase comparator for the high frequency ultrasonic signal up to 1 GHz. For the low temperature measurement with the dilution refrigerator, the coaxial air line and the cryo-amplifier up to 1 GHz have been developed. Furthermore the various sample-orienting devices of the spiral gear and the two-circle goniometer have been designed. In the acoustic de Haas-van Alphen measurements, we focused the various heavy Fermion compounds. In particular we successfully observed the heavy hole state in CeSb. This result provides an essential evidence for the p-f mixing mechanism in CeSb proposed by Kasuya et al. And the observed large oscillatory intensity is due to the remarkable enhancement of the density of state in the hole state. The experiment of the acoustic dHvA effect and the oscillatory magnetostriction may provide rich information on the unusual character of the electron- strain interaction in the heavy Fermion and superconducting compounds. Anyway further continuous research with the ultrasonic method should be required.