OBSERVATION OF HYSTERESIS AT THE SPIN-FLOP TRANSITION INDUCED BY A PULSED MAGNETIC-FIELD

We present the results of diffraction research on the spin-flop transi tion in alpha-Fe2O3 and Cr2O3 performed on the SNIM-2 spectrometer of the IBR-2 pulsed reactor using a pulsed magnetic field. The field puls es had a sinusoidal form with a time duration of 400-1000 mu s. The hy steresis dependences of the scattering intensity on the field value we re obtained. In the case of hematite, with a change in amplitude of th e magnetic pulses, the hysteresis loop takes its utmost shape and widt h, which do not change with further increases in amplitude. The width of the utmost loop is almost one order less than the theoretical range of metastability of the phase states. With decreasing temperature the width of the utmost loop decreases. In the case of Cr2O3, hysteresis is observed at magnetic field amplitudes which do not reach the critic al value for phase transition. This testifies to a delay of the turnin g process of sublattice magnetization in the initial phase state.