Large magnetic-field-induced strain at the magnetic order transition in triangular antiferromagnet AgCrS₂

Strain induced by a magnetic field is common phenomenon for ferromagnets, but few antiferromagnets show large strain field. On the basis of linear measurements sintered samples triangular antiferromagnet ACrS2 (A = Cu, Ag, and Au) in fields up to 9 T, AgCrS2 sample was found strain, yielding volume change over 700 ppm, which one largest changes measured date an antiferromagnet. This appeared only at Néel temperature 42 K not restored its initial state when applied decreased zero; however, it initialized cooling far below temperature. These results suggest that coexistence magnetically ordered paramagnetic phases first-order phase transition plays important role. AuCrS2 showed field-induced with similar features although smaller than AgCrS2.