  We present a large magnetodielectric (MD) effect of 65 % at 100 kHz with 5 T
field in B-site ordered La2CoMnO6 (LCMO) polycrystalline sample. Frequency and
temperature dependent impedance and dielectric studies under magnetic field
divulge both intrinsic and extrinsic origins for the observed MD effect. The
temperature dependent Raman spectroscopy measurement has shown 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.
