Acoustical measurements on the heavy fermion compound URu2Si2 in pulsed magnetic fields

Abstract The ultrasonic properties of a URu 2 Si 2 single crystal were measured in pulsed (25 ms) magnetic fields up to 50 T. In the frequency range from 20 to 200 MHz, both the attenuation and velocity of sound change markedly in the vicinity of the metamagnetic transitions (near 40 T). The data for URu 2 Si 2 show three transitions, in agreement with earlier magnetization results of other authors. A unique fast data-acquisition ultrasonic spectrometer was assembled and utilized for these studies.