Magnetocaloric effect and spin-phonon correlations in RFe0.5Cr0.5O3 (R = Er and Yb) compounds

TL;DR

This study explores the magnetic, dielectric, and spin-phonon interactions in RFe0.5Cr0.5O3 compounds with R = Er and Yb, revealing complex magnetic transitions, magnetocaloric effects, and charge carrier dynamics.

Contribution

It provides new insights into the spin-phonon coupling and magnetocaloric properties of mixed RFe0.5Cr0.5O3 oxides, highlighting differences between Er and Yb variants.

Findings

ErFe0.5Cr0.5O3 exhibits multiple spin reorientation transitions.

YbFe0.5Cr0.5O3 shows a single spin reorientation transition.

Significant magnetocaloric effect observed near the second SR transition in ErFe0.5Cr0.5O3.

Abstract

We report the results of our investigation of the physical properties of mixed metal oxides RFe0.5Cr0.5O3 (R = Er and Yb). ErFe0.5Cr0.5O3 undergoes an antiferromagnetic ordering around 270 K followed by spin reorientation (SR) transitions around 150 and 8 K respectively. In contrast, in YbFe0.5Cr0.5O3 a single SR transition is noted at 36 K, below the AFM ordering temperature of 280 K. In ErFe0.5Cr0.5O3, a significant value of magnetic entropy change ({\Delta}SM) ~ -12.4 J/kg-K is noted near the 2nd SR transition, however, this value is suppressed in YbFe0.5Cr0.5O3. Temperature dependent dielectric permittivity of ErFe0.5Cr0.5O3 and YbFe0.5Cr0.5O3 at different frequencies, reveal the presence of Debye-like relaxation behaviour in both compounds, which can be due to the effect of charge carrier hopping between localized states of Fe and Cr ions. Temperature dependent Raman scattering studies divulge that spin-phonon coupling plays a crucial role in defining the physical properties of these compounds.