De Haas-van Alphen Effect in Rare-earth Gallium Compounds RGa2

利用该资助购买的10块超导磁体构建了德哈斯-凡阿尔芬效应的测量系统。在5T ~ 10t的温度范围内，利用该测量系统测量了反铁磁SmGa2和PrGa2及其参比物质LaGa2在4He温度范围内的dHvA效应。测量结果如下：(1)反铁磁SmGa2和PrGa2的费米表面与LaGa2非常相似，尽管这两种化合物的4-f态不同。(2)在PrGa2和SmGa2中观察到的超磁相变导致了电子自旋和4-f轨道自旋之间的场诱导交换相互作用。(3)费米表面嵌套效应稳定了PrGa2的调制磁结构。(4) SmGa2中反铁磁态的费米面与顺磁态的费米面不同。(5) SmGa2中存在s-f混合效应导致的电子质量增强。我们将继续研究dHvA对重稀土原子和Ga化合物的影响。

The measuring system of de Haas-van Alphen effect using the 10 superconducting magnet purchased with this grant-in aid was constructed. We have measured the dHvA effect of antiferromagnetic SmGa2 and PrGa2, and their reference substance LaGa2 in the 4He temperature range with use of this measuring system in the field ranging from 5T to 10 T.We have obtained the following results from the measurement. (1) The Fermi surfaces of antiferromagnetic SmGa2 and PrGa2 are very similar to that of LaGa2 in spite of differences in 4-f states in these compounds. (2) Metamagnetic phase transition observed in PrGa2 and SmGa2 results in the field induced exchange interaction between electron spin and 4-f orbital spin. (3) The nesting effect of the Fermi surface stabilizse the modulated magnetic structure observed in PrGa2. (4) The Fermi surfaces for antiferromagnetic state differ from that of paramganetic state in SmGa2. (5) The electron mass enhancement due to s-f mixing effect is suggested to occur in SmGa2.We will continue to invesigate the dHvA effect on compounds of heavy rear-earth atoms and Ga.