Two polymorphs of a new intermetallic Ce2Rh2Ga - crystal structure and physical properties

JOURNAL OF ALLOYS AND COMPOUNDS

卷:844

Article

Nesterenko, Sergey¹  Tursina, Anna¹  Pasturel, Mathieu²  Xhakaza, Sindisiwe³  Strydom, Andre^3,4 

[1] Lomonosov Moscow State Univ, Dept Chem, Moscow 119991, Russia

[2] Univ Rennes, CNRS, ISCR UMR6226, F-35000 Rennes, France

[3] Univ Johannesburg, Phys Dept, Highly Correlated Matter Res Grp, POB 524, ZA-2006 Auckland Pk, South Africa

[4] Max Planck Inst Chem Phys Solids, 40 Nothnitzerstr, D-01187 Dresden, Germany

关键词: Cerium intermetallics;    Gallides;    Crystal structure;    Magnetic properties;   

DOI  :  10.1016/j.jallcom.2020.155570

来源: Elsevier

【 摘 要 】

We report on the synthesis and physical properties of the new ternary intermetallic Ce2Rh2Ga. Its formation and dimorphism have been investigated by powder and single crystal X-ray diffractometry, as well as by differential thermal analyses. LT-and HT-Ce2Rh2Ga can be obtained by the chosen respective thermal treatment. The high-temperature form (HT-Ce2Rh2Ga), stable above 864(5)degrees C, is orthorhombic La2Ni3-type [Cmce, oS20, a = 5.851(2) angstrom, b = 9.6184(19) angstrom, c = 7.4871(17) angstrom, V = 421.3(2) angstrom(3)]; the low temperature form (LT-Ce2Rh2Ga), stable below this temperature, is monoclinic Pr2Co2Al-(Ca2Ir2Si-) type [C2/c, mS20, a = 10.0903(6) angstrom, b = 5.6041(3) angstrom, c = 7.8153(4) angstrom, b = 104.995(3)degrees C, V = 426.88(4) angstrom 3]. The magnetic measurements were conducted on two different samples, namely on the LT-Ce2Rh2Ga and the other on the HT-Ce2Rh2Ga sample. The HT-Ce2Rh2Ga compound is found to exhibit a phase transition at 128.5 K. By virtue of the sharp peak anomaly in the temperature dependence of the magnetic susceptibility this phase transition is plausibly of antiferromagnetic origin, but occurs at a remarkably high temperature compared to what is typical for Ce binary and ternary compounds. LT-Ce2Rh2Ga has a ground state of ferromagnetic nature which sets in at a paramagnetic-to-ferromagnetic phase transition at 5.2 K. (C) 2020 Elsevier B.V. All rights reserved.

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