Magnetoelastic coupling in DyMn2O5 via infrared spectroscopy

Abstract

We investigated the infrared-active phonons in DyMn2O5 as a function of temperature and magnetic field in order to elucidate the magnetic ordering-induced lattice distortions. Spin-lattice coupling in this geometrically frustrated multiferroic is evidenced by small frequency shifts of several phonon modes at various magnetic ordering temperatures, vibrational frequency shifts between 60 and 65 K from which we extract large coupling constants, and magnetic-field dependence of numerous phonons. We analyze these results in terms of local lattice distortions and discuss the consequences for the ferroelectric polarization and magnetodielectric effect.