抄録
Phonon dynamics of multiferroic Sr0.5Ba0.5Mn0.97Ti0.03O3 was investigated by means of inelastic x-rays cattering. We found that the mode which corresponds to the soft mode in the paraelectric materials becomes prominent below the antiferromagnetic phase transition temperature. On the other hand, the energies of transverse optical phonon modes remain almost constant upon the magnetic ordering. This suggests that dynamical fluctuation of electric dipole moments is crucial for a large spin-phonon coupling.
