Magnetic anisotropy of UTe

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

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

Uranium chalcogenides is a large group with many interesting compounds. Some of the examples are -US in which metallic state can be induced by magnetic field, and newly discovered spin-triplet superconductor UTe which exhibits complex phase diagram in applied magnetic field and in hydrostatic pressure. One of the compounds belonging to the group is UTe which crystallizes in noncentrosymmetric P-6 (174) space group. The crystal structure is complicated with three unequal positions for uranium atoms and four unequal positions for tellurium atoms. Complex uranium systems were recently suggested to host heavy-fermion behavior by Svanidze et. al. Published magnetic properties of polycrystalline sample suggest ferromagnetic behavior with Curie temperature of 54 K. We present magnetic, transport and thermodynamic results obtained on single crystal of UTe. Single crystals were obtained by chemical vapor transport method. UTe shows ferromagnetic ordering of magnetic moments in basal plane below 48 K. Around 26 K additional ordering is observed in the c-axis direction. Electric transport shows semimetallic behavior. We will discuss unusual behavior of magnetism in connection with crystal structure and unequal uranium positions.