Experimental evidence for a field-induced transition between two types of domain walls in antiferromagnets

The existence of a field-induced transition between two types of domain walls is inferred from the field dependence of the rotational hysteresis, as observed in the spin-flop state of the biaxial antiferromagnet (C₂H₅NH₃)₂CuCl₄. In the spin-flop state a weak-ferromagnetic (WF) moment is present along the difficult axis; the hysteresis is connected with irreversible domain-wall movements, the leverage on the walls being provided by the WF moment in the external field.