Evidence of spin-phonon interactions in MgCu₂O₃: low temperature Raman studies

Abstract

Experimental low temperature Raman spectroscopy studies upto the temperature of 83 K were performed on MgCu2O3 compound using 785 nm excitation source. Experimentally obtained Raman spectra compare well with those obtained from DFPT calculations. Phonon modes show different behaviour below and above the Néel temperature ~95 K. Anharmonic contribution is prominent above the Néel temperature but a significant departure from the anharmonic behaviour was observed for certain Ag and B3g modes below the Néel temperature. This behaviour is attributed to spin-phonon coupling present in the compound. The spin-phonon coupling arises due to modulation in the exchange integral by the lattice vibrations. The atomic vibrations of each mode and their effect on the exchange integral are discussed.