High field magnetism and magnetoacoustics in UCu0.95Ge

Studies of magnetic and magneto-acoustic characteristics of the intermetallic compound UCu0.95Ge with antiferromagnetic ground state have been performed on single crystals in pulsed magnetic fields up to 64 T applied along the main axes. Along the a axis, a first-order phase transition has been observed at 61 T. For the field applied along the c axis, the first-order phase transition occurs at a much lower magnetic field (38 T). In both directions, the magnetization trends to saturate at 1.35 μB per formula unit. These field-induced transitions as well as the spontaneous transition at the magnetic ordering at TN = 48 K are accompanied by pronounced anomalies in the sound velocity and sound attenuation. The field-temperature phase diagrams are constructed for both directions of the magnetic field. The results of our theoretical analysis within the framework of the mean-field approximation qualitatively agree with the observed behavior of magnetic and magneto-acoustic characteristics of UCu0.95Ge.

► High-field magnetization and magnetoacoustic studies on a UCuGe single crystal are performed in pulsed magnetic fields up to 65 T.
► The antiferromagnetic ordering and the field-induced phase transitions at 61 T (along a-axis) and 38 T (along c-axis) are accompanied by pronounced acoustic anomalies.
► The observations qualitatively agree with the developed theory.