Spin-reorientation and multidomain states in the spin-flop region of uniaxial antiferromagnets

Abstract Based on an effective phenomenological energy, a strongly pronounced two-scale character is demonstrated for magnetic states of easy-axis antiferromagnets. Near the spin-flop field, magnetic properties are determined by weaker interaction terms than those in the major part of the magnetic phase diagram. Field and angular dependencies of the magnetic susceptibility tensor are calculated for homogeneous and multidomain states. Their peculiarities in the vicinity of the spin-flop can be employed for investigations on magnetic states and material parameters of easy-axis antiferromagnets. Corresponding experiments on the orthorhombic layered antiferromagnet ( C 2 H 5 NH 3 ) 2 CuCl 4 are presented. The evolution of multidomain states and their phase boundaries are determined in the spin-flop region.