PULSE-FIELD EXPERIMENTS ON THE SPIN-LATTICE INTERACTION IN LOW-DIMENSIONAL SPIN SYSTEMS

摘要

Low-dimensional spin systems reveal new and unexpected physical phenomena such as distinct plateaus in the magnetization as a function of magnetic field. In this paper we present ultrasonic measurements for the quasi-two-dimensional spin system SrCu_2(BO_3)_2 in magnetic fields up to 50 T. From this technique we obtained detailed information about the spin State, the magnetic excitations and their interaction with phonons. The dimerized quantum-spin system SrCu_2(BO_3)_2 exhibits plateaus in the magnetization and shows surprisingly strong magneto-elastic effects as a function of temperature and magnetic field. The pronounced elastic anomalies indicate a resonant interaction between the sound wave and the magnetic excitations.