| Summary: | 碩士 === 國立成功大學 === 物理學系 === 107 === RE2Ru3Ge5 (RE = Pr, Sm) have two structures. One is Sc2Fe3Si5. The other is U2Co3Si5. There are already related studies about Sc2Fe3Si5-type RE2Ru3Ge5. Although some papers reported that U2Co3Si5-type Pr2Ru3Ge5 and Sm2Ru3Ge5 were manufactured by means of arc-melting, the information of physical properties of U2Co3Si5-type RE2Ru3Ge5 (RE = Pr, Sm) is still lacking. In addition, there are two methods for manufacturing RE2Ru3Ge5(RE = La, Ce). One is In-flux and the other is arc-melting. La2Ru3Ge5 and Ce2Ru3Ge5 prepared through In-flux are not large enough for measurements of general physical properties13. La2Ru3Ge5 and Ce2Ru3Ge5 have already been produced by arc-melting, but there are only results for crystal structure analysis and no experimental results of physical properties. Therefore, we use arc-melting to prepare U2Co3Si5-type RE2Ru3Ge5 (RE = La, Ce, Pr, Sm). They are explored by measuring electrical resistivity, Seebeck coefficient, thermal conductivity, specific heat, and magnetic susceptibility. From these experimental results, La2Ru3Ge5 behaves as an ordinary metal. However, Ce2Ru3Ge5, Pr2Ru3Ge5, and Sm2Ru3Ge5 exhibit variations at around temperature of the variations T＊∼170, ∼140, and ∼245 K, respectively. In addition, the results of the synchrotron X-ray powder diffraction(SXRD) below and above T＊ confirm the appearance of the lattice distortion for Sm2Ru3Ge5. According to these results, Sm2Ru3Ge5 is a possible charge density wave (CDW) material.
|
|---|
