Ferromagnetic Crossover within the Ferromagnetic Order of U$_{7}$Te$_{12}$

TL;DR

This study explores the magnetic properties and phase transitions of U7Te12, revealing a ferromagnetic transition at 48 K and a crossover at 26 K involving moment reorientation or multiple uranium site ordering.

Contribution

It provides detailed insights into the magnetic phase behavior and site-specific ordering in U7Te12, highlighting a crossover phenomenon not associated with a specific heat anomaly.

Findings

Ferromagnetic transition at 48 K with in-plane magnetization increase

Rapid out-of-plane component increase below 26 K indicating a crossover

No lambda anomaly in specific heat at the crossover temperature

Abstract

We investigate the physical properties of a single crystal of uranium telluride U$_{7}$Te$_{12}$. We have confirmed that U$_{7}$Te$_{12}$ crystallizes in the hexagonal structure with three nonequivalent crystallographic uranium sites. The paramagnetic moments are estimated to be approximately 1 $\mu_{\rm B}$ per the uranium site, assuming a uniform moment on all the sites. A ferromagnetic phase transition occurs at $T_{\rm C}=48$ K, where the in-plane magnetization increases sharply, whereas the out-of-plane component does not increase significantly. With decreasing temperature further below $T_{\rm C}$ under field-cooling conditions, the out-of-plane component increases rapidly around $T^{\star}=26$ K. In contrast, the in-plane component hardly changes at $T^{\star}$. Specific heat measurement indicates no $\lambda$-type anomaly around $T^{\star}$, 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.