Elecronic critical phenomena under microgravity and gravity circumstances

在这一科学计划中，我们研究了微重力条件下和重力条件下临界混合液态合金的两相分离(TPS)，特别是临界现象中的电子性质。在实验室里研究了液态Hg-Ga、Cd-Ga和BiGa合金的电阻率R。即使在临界浓度(CC)附近，电阻率的浓度依赖关系R也表现出单调变化。然而，在CC附近，液态BiGa和Cd-Ga合金的电阻率温度系数(TCR)表现出最大值，而液态Hg-Ga合金表现出最小的行为。测量的液态铋镓合金在微重力下的TCR随浓度的变化表现出更大的最大值，这是由日本空间与宇航科学研究所(ISAS)发射的S520-19火箭实现的ELM计划。这些行为可以用临界点(CP)附近浓度波动的增长程度来解释。此外，从R在冷却过程中的行为中提取了均质液体(HL)的过冷行为。在微重力条件下，BiGa在HL区的过冷度远大于重力条件下的过冷度。微重力条件为研究过冷和失稳行为提供了理想的环境。

In this science plan the two phase separation (TPS) for liquid alloys with critical mixing was investigated both under microgravity condition and under gravity condition with particular interest in the electronic properties in the critical phenomena. The electricl resistivity, R,was studied for liquid Hg-Ga, Cd-Ga and Bi-Ga alloys in a laboratory on the ground. The concentration dependence of resistivity, R,show a monotonous variation even around the critical concentration (CC). However, the temperature coefficients of resistivity (TCR) around CC show maximum behaviors for liquid Bi-Ga and Cd-Ga alloys and a minimum behavior for liquid Hg-Ga alloys. The concentration dependence of measured TCR for liquid Bi-Ga alloys shows a far larger maximum behavior at CC under microgravity, which was realized as the ELM project by the launch of S520-19 rocket belonging to the Institute of Space and Astronautical Science (ISAS) in Japan. These behaviors are explained by the degree of growth of concentration fluctuations near the critical point (CP). In addition to these, the supercooling behavior of homogeneous liquid (HL) was extracted from the behavior of R on cooling process. The degree of supercooling for Bi-Ga in the HL range was far larger under microgravity than under gravity conditions. The microgravity condition provides an ideal circumstance for the study of supercooling and spinodal behaviors.