Phase coexistence and the magnetic glass-like phase associated with the Morin type spin reorientation phase transition in SmCrO3

Abstract

The phenomenon of spontaneous spin reorientation phase transition (SRPT) in SmCrO₃ has been considered as a process comprising continuous rotation of magnetic moments of chromium ions. It is observed that in the vicinity of SRPT, the cooling and warming magnetic curves follow distinctly different paths and in the presence of low measuring fields this thermal irreversibility extends up to the Néel temperature marking a remarkable width of ∼163 K. Investigating the origin of thermal hysteresis and henceforth the nature of SRPT, we have qualitatively determined the phase fractions of phases involved in the transition. The thermal evolution of phase fraction closely resembles the theoretically predicted phase evolution in the well known Arvami model. The close resemblance suggests that the growth and nucleation mechanism across SRPT is similar to the crystallization process of solids from a supercooled liquid and further confirms the coexistence of two metastable phases in the neighborhood of SRPT. Moreover, the signatures of the magnetic glass like phase, which mainly arises due to the arrest of kinetics during a first order transition, are also noticed below T_SRPT. These observations suggest the discontinuous Morin type nature of the spin reorientation process due to discrete flipping of Cr³⁺ ions from the high temperature Γ₄ to low temperature Γ₁ configuration.