ALBERT

Description: Detailed magnetically tunable ac electrical properties of x La 0.7 Sr 0.3 MnO 3 (LSMO)–(1 − x) ErMnO 3 (EMO) (x = 0.1, 0.3, and 0.5) multiferroic nanocomposites have been studied at 300 K in presence of varying magnetic field (H appl ), applied both in parallel and perpendicular configuration with respect to the measuring electric field. AC electrical properties have exhibited significant variation with H appl for all composites, whereas for parallel configuration of H appl such effect is very feeble for x = 0.3 composite. We have attributed this anisotropic behavior to the demagnetization effect in the sample. In contrast, for x = 0.1 and 0.5 composites, no such anisotropy effect is experimentally evidenced. Impedance and real part of impedance have been found to decrease with H appl at low frequency ( f ) region. We attribute this observation to the depinning of the magnetic domain walls from the grain boundaries pinning centers and thereby enhancing the spin dependent transport in the composite. For x = 0.3 composite, Nyquist plots have been fitted considering dominant contributions of LSMO and EMO grain boundaries and the interface region between them. However, for x = 0.1 composite, it corresponds to EMO grain boundaries and grain boundary interface region. The relaxation frequency ( f R ) is observed to shift at higher/lower f region in perpendicular/parallel configuration of H appl for x = 0.3 composite. This opposite variation of f R s with H appl for perpendicular and parallel configurations has been attributed to two competing factors of H appl induced enhancement of inductive part and H appl enhanced spin dependent transport causing fast relaxation processes in the sample. For x = 0.1 composite, in both configurations of H appl , f R s is shifting towards high f region, which has been discussed in terms of dominant role of spin dependent transport.