Ferromagnetic crossover within the ferromagnetic order of UTe

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

We investigate the physical properties of a single crystal of uranium telluride UTe. We have confirmed that UTe crystallizes in the hexagonal structure with three nonequivalent crystallographic uranium sites. The paramagnetic moments are estimated to be approximately 1 per the uranium site, assuming a uniform moment on all the sites. A ferromagnetic phase transition occurs at = 48 K, where the in-plane magnetization increases sharply, whereas the out of-plane component does not increase significantly. With decreasing temperature further below under field-cooling conditions, the out-of-plane component increases rapidly around T= 26 K. In contrast, the in-plane component hardly changes at T. Specific heat measurement indicates no -type anomaly around T, so this is a cross-over suggesting a reorientation of the ordering moments or successive magnetic ordering on the part of the multiple uranium sites.