Magnetostriction of the antiferromagnet NiCl2 in the homogeneous and multidomain states

Experimental data from measurements of the induced magnetostriction of the easy-plane two-sublattice layered antiferromagnet NiCl2 in the homogeneous and multidomain states at T=4.2 K are analyzed. It is shown that the intersublattice magnetoelastic interactions are dominant in NiCl2. The induced magnetostriction of the crystal in the single-domain state is due to canting of the spins of the sublattices toward the magnetic field direction. The induced magnetostriction in the multidomain state is due to a rearrangement of the domain structure and is independent of the small in-plane anisotropy. In both cases the values of the induced magnetostriction are directly proportional to the square of the value of the external magnetic field.