Specific features of the magnetic field-induced orientational transition in EuMnO3

It is found that the spin-flop transition in EuMnO3 manganite induced by a magnetic field H parallel to the b axis is accompanied not only by a magnetization jump and magnetostriction anomalies but also by the appearance of electric polarization in the vicinity of the transition field Hcr ∼ 200 kOe. This phenomenon can be associated with the occurrence of magnetically inhomogeneous (modulated) states in the vicinity of Hcr. In these states, the system loses the center of symmetry, which allows for the appearance of the polarization. The formation of such states in a magnetic field is caused by the general tendency of the occurrence of magnetically inhomogeneous (incommensurate) structures in the RMnO3 series due to the frustration of exchange interactions with decreasing ionic radius of the rare-earth ion R starting with R = Eu.