Irreversible transitions in the exchange-striction model of spin-glass state

Abstract

Based on the assumption of a negative volume dependence of random exchange integrals, it is possible to switch to a compressible Sherrington–Kirkpatrick spin-glass model. Within the proposed model, temperature–pressure phase diagrams were calculated and pressure- and magnetic-field-induced first-order phase transitions from the initial paramagnetic and spin-glass states to the ferromagnetic state were predicted. It was shown that the application of pressure in the spin-glass state not only increases and shifts magnetic susceptibility, but also reduces the critical magnetic fields of irreversible induced phase transitions from the spin-glass to the ferromagnetic state. The obtained results are used to describe the spin-glass state in (Sm1–xGdx)0.55Sr0.45MnO3.