Thermal expansion of samarium - terbium orthoferrites in the spin reorientation range

摘要

On the basis of studies of the thermal expansion of samarium - terbium orthoferrites (STO) in the range of spin reorientation with the help of crystallo-optical and magnetic property data a new model of the transition is discussed. For STO the direction of magnetic momentum alters from axis [100] towards [001] in the range 220 - 290 K. The conclusion was drawn that zero values of thermal expansion of STO in the range of the intermediate state correspond to the coincidence of the magnetic momentum direction with the crystallographic direction [110].