Phase stabilization of double perovskite Sm2FeMnO6 and the study on its Structural, magnetic and dielectric properties

Abstract

Sm2FeMnO6 offers combined physical properties of two single perovskite compounds SmFeO3 and SmMnO3, making it a technologically feasible functional material. Sm2FeMnO6 crystallizes in a distorted orthorhombic Pbnm symmetry with lattice parameters a = 5.3805(2) Å, b = 5.6182(2) Å and c = 7.6434(3) Å. The Fe/Mn cation arrangement is found to be random in this symmetry. The phonon modes concurrent to the existence of (Fe/Mn)O6 octahedra and Jahn-Teller distortion due to Mn ions are found. Both Fe and Mn ions present at the B-octahedral sites have trivalent state. Temperature and field dependent magnetization measurements on Sm2FeMnO6 illustrate multiple transitions. A distinctive switching associated with a spontaneous spin-flip transition of Sm and Mn/Fe sublattices are observed at 201 K and 206 K in ZFC and FC curves respectively. The antiferromagnetic to paramagnetic transition occurred at a Neel temperature of 491 K. The transition temperatures are lowered compared to the reported single perovskite SmFeO3 indicating the influence of Mn ions on the magnetic exchange integral chains. Thermally activated dielectric relaxation processes are observed in the temperature range 300 K to 500 K and near 700 K. The anomaly is found to exist in the magnetic transition region, evidencing the coupling of magnetic order with electric order parameter. Thus, the collective effect of Fe and Mn ions at the B-site on various physical properties of Sm2FeMnO6 opens up new avenues in the field of magnetoelectric applications.