Evidence of spin-phonon interactions in MgCu 2 O 3 : low temperature Raman studies

Experimental low temperature Raman spectroscopy studies upto the temperature of 83 K were performed on MgCu 2 O 3 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 A g and B 3 g 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.