Investigation of the intrinsic magnetodielectric effect in La2CoMnO6: role of magnetic disorder

Abstract

We present a large magnetodielectric (MD) effect of 65% at 100 kHz with a 5 T field in a B-site ordered La₂CoMnO₆ (LCMO) polycrystalline sample. Frequency and temperature dependent impedance and dielectric studies under a magnetic field divulge both intrinsic and extrinsic origins for the observed MD effect. The temperature dependent Raman spectroscopy measurement showed spin–lattice coupling that supports the intrinsic origin of the observed large MD response in LCMO. Extrinsic contributions to MD response mainly originate from disorder and interface effects; here, we signify this by hole carrier (Sr) doping at the A-site of the ordered LCMO sample. The comparison study has disclosed that with the disorder, the intrinsic polarization due to asymmetric hopping decreases significantly, and the disorder induced transport dominates in both MD and magnetoresistance behaviour with close resemblance.