Spin reorientation transition and coupled spin-lattice dynamics of Sm0.6Dy0.4FeO3

Abstract

In this work, we have presented a solid-solution of Sm0.6Dy0.4FeO3 in the form of nano-particles having spin reorientation transition (SRT) at a temperature interval of 220–260 K. The lattice dynamics of Sm0.6Dy0.4FeO3 have investigated by temperature-dependent x-ray diffraction and Raman spectroscopy. A negative thermal expansion at low temperatures has observed, which might be due to the interaction between Sm3+ and Fe3+ sublattice. Anomalous behavior in lattice parameters, octahedral tilt angle, and bond lengths have observed in the vicinity of SRT, which confirms the existence of magneto-elastic coupling in the system. The strong anomaly has observed in linewidth and phonon frequencies of Raman modes around SRT, which may be related to the spin–phonon coupling in Sm0.6Dy0.4FeO3. The contribution of SRT in lattice change and the presence of spin–phonon coupling can help to understand the correlation between the magnetic and structural properties of orthoferrite.