High field magnetization of UOX (X = S and Se)

Opletal, P.  ; 酒井 宏典   ; 芳賀 芳範   ; 三宅 厚志*; 徳永 将史*; 常盤 欣文  ; 山本 悦嗣  ; 神戸 振作  ; 徳永 陽  

Opletal, P.; Sakai, Hironori; Haga, Yoshinori; Miyake, Atsushi*; Tokunaga, Masashi*; Tokiwa, Yoshifumi; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo

UOX (X = S, Se, Te) crystallizes in tetragonal PbFCl-type structure (P4/nmm space group). Only polycrystalline samples are reported in literature. UOS, UOSe and UOTe were reported to be antiferromagnets with TN = 55, 100 and 160 K, respectively. We have presented recently that TN in UOS is much higher (TN = 82 K) and all compounds behave like semimetals. Magnetic structure of UOS and UOSe were reported to have moment along the c-axis with Q = (0,0,1/2). UOTe was theoretically predicted to have nontrivial topology. We will present the results of magnetization measurements in high magnetic fields for UOS and UOSe and their phase diagrams and their tricritical point. We will compare our results to current understanding of tricritical points in antiferromagnet and discuss possible scenarios.