Thermal expansion and relaxation of magnetostriction in a metastable state of dysprosium orthoaluminate

A study of thermal expansion and magnetostriction caused by the metamagnet phase transition in a rare earth sublattice was performed for a DyAlO$_3$ single crystal, which is the model object of a wide family of rare earth oxides with the structure of distorted perovskite. The sharp variation of the relative strains along the $b$ axis ${3.6\cdot10^{-5}}$ was found at ${T\cong2.18}$ K. The nature of the observed anomaly is caused by the occurrence of a metastable state of the magnetic subsystem achieved in the conditions of the experimental process. The relaxation of magnetostriction is studied and the exponential character is found. The possible mesoscopic nature of thermal and quantum mechanisms of magnetic relaxation is considered.