Direct Evidence of Simultaneous Reversal of Ferrimagnetically Coupled Sm 4f and Mn 3d Angular Momenta in SmMnO3

Using the soft X-ray magnetic circular dichroism (XMCD) technique, we investigated the magnetic states of the Sm 4 f and the Mn 3 d moments in a Néel N -type ferrimagnet, SmMnO 3 , which exhibits a striking magnetocapacitive effect around the compensation temperature ( T comp ≈ 9.4 K). The XMCD results show that the Sm 4 f and the Mn 3 d moments were always aligned antiparallel to each other and that, upon sweeping a magnetic field, the angular momenta of Sm 4 f and Mn 3 d were simultaneously reversed at the field where the magnetocapacitive effect was observed. This indicates that the magnetocapacitive effect of SmMnO 3 is induced by a simultaneous reversal of Sm 4 f and Mn 3 d angular momenta, i.e. , magnetization reversal. We discuss a plausible origin of the magnetocapacitive effect in terms of the p-d hybridization mechanism.