Magnetostriction and piezomagnetism of noncollinear antiferromagnet Mn₃NiN

Abstract

Abstract Magnetoelastic effects in the three-sublattice noncollinear antiferromagnet Mn3NiN are studied theoretically. Shear deformations are shown to give rise in the crystal to a piezomagnetic moment of an exchange nature. The magnitude of the piezomagnetic moment is comparable with the weak ferromagnet moment detected experimentally in Mn3NiN. The absence of critical softening of sound waves near spinorientational phase transitions is demonstrated. It is proved that the experimentally observed temperature hysteresis at a first-order phase transition from the para- to antiferromagnet state is due to exchange magnetostriction. Key Words: Magnetoelastic effectpiezomagnetismnoncollinear antiferromagnetMn3NiNfirst-order phase transition