Domain-wall dynamics in the disordered ferromagnetLaMnO3.075

Abstract

Low-field ac susceptibility measurements have been made on the cation-deficient perovskite manganite ${\mathrm{LaMnO}}_{3.075}.$ As the temperature is increased toward ${T}_{C}$ (122 K), the real part of the ac susceptibility $({\ensuremath{\chi}}^{\ensuremath{'}})$ exhibits discontinuous jumps at roughly regular intervals, followed by gradual decays on the high-temperature side, resulting in a series of spikes in the ${\ensuremath{\chi}}^{\ensuremath{'}}$ vs temperature plot. It is argued that the spikes appear as a consequence of disaccommodation, combined with periodic, spontaneous domain-wall jumps.