Correlation between spin-phonon coupling and magneto-electric effects in CoFe2O4/PMN-PT nanocomposite: Raman Spectroscopy and XMCD study

TL;DR

This study explores the spin-lattice coupling and magneto-electric effects in CoFe2O4/PMN-PT nanocomposites, demonstrating how interfacial strain influences magnetic and electric properties through Raman, XMCD, and magnetization measurements.

Contribution

It provides new insights into strain-mediated spin-lattice and magneto-electric coupling mechanisms in CoFe2O4/PMN-PT composites, confirmed by spectroscopic and magnetic analyses.

Findings

Lattice modifications occur across PMN-PT's Curie temperature.

Magnetic moment drops sharply at Tc of PMN-PT.

Enhanced magneto-electric coefficient after electric poling.

Abstract

We have investigated the coupling of lattice with spin via strain interactions in the CoFe2O4/PMN-PT composite system. X-ray diffraction and Raman spectroscopic studies illustrate a remarkable modification in CoFe2O4lattice across Curie temperature (450 K) of PMN-PT. Subsequently, CoFe2O4/PMN-PT composite reveals a sudden drop in magnetic moment across Tc of PMN-PT (450 K). However,theindependent CoFe2O4phasedisplaystypical ferromagnetic behaviour across this temperature. These findings establish spin-lattice coupling owing to th interfacial strain transfer between CoFe2O4 and PMN-PT in composite. The strain intractions leads to magneto-electric coupling, evidenced by measuring magentization and magneto-electric coefficient for the electric field poled and unploed CoFe2O4/PMN-PT composite samples. X-ray magnetic circular dichroism (XMCD) analysis establishes that the cation (Fe3+/Co2+) redistribution occurs on tetrahedral and octahedral site in the electrically poled CoFe2O4/PMN-PT composite, confirming the coupling between magnetic and electric ordering in the composite. The magneto-electric coupling coefficient alpha vs dc magnetic field curves revealed hysteretic behavior and enhanced {\alpha} values after electric poling, which originates from the strain induced modifications in the magnetic domains configuration of composite in the poled samples. These findings suggest that the existence of spin lattice coupling may leads to the mechanism of strong magneto-electric effects via strain interactions in CoFe2O4/PMN-PT composite.