Parity effect in the resonant tunneling

A mechanism causing the parity effect, i.e., the alternate change of the amplitude of the relaxation in the sequence of thermally assisted resonant tunneling, is proposed from the viewpoint of nonadiabatic transitions between thermally excited states. In this mechanism, alternating enhancement of the relaxation is naturally understood as a general property of uniaxial magnets in a sweeping field at finite temperatures at which appreciable populations are pumped into excited states. It is also found that the sequence of the enhanced relaxation depends on the sweeping rate of the field.