Magnetostriction and magnetic torque measurements of uranium monosulfide single crystals*

The family of actinide compounds AX, where A = actinides and X = N, P, As, Sb, S, Se, and Te have drawn great interest in research of actinide compounds because of their simple structure and rich magnetic properties. Recent study of UO₂ and UN revealed the effectiveness in probing the magneto-structural coupling in actinides by high magnetic field magnetostriction. Uranium monosulfide (US) crystalizes in simple cubic rock salt structure and exhibits the highest ferromagnetic transition temperature in uranium monochalcogenides (T_C = 177 K) with easy axis along [111] direction. At the magnetic phase transition the crystal structure undergoes a rhombohedral distortion along one of the [111] directions with a large magnetic anisotropy. This might imply that strong magneto-elastic interactions play important role in this material. In this talk, our recent measurements of the magnetostriction and magnetic torque of uranium monosulfide single crystals will be presented.