Spin reorientation transition and coupled spin-lattice dynamics of Sm 0.6 Dy 0.4 FeO 3 .

In this work, we have presented a solid-solution of Sm0.6Dy0.4FeO3 in the form of nanoparticles having spin reorientation transition (SRT) at a temperature interval of 220 K-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.