Tuning electronic transport through magnetic field and magnetoelectric coupling of multiferroic nanocomposites

Abstract

Detailed analysis on structural, dielectric and ac electrical transport with dc magnetic field variation and magnetoelectric response are studied on semiconductor based multiferroic La0.7Sr0.3MnO3 - ZnO nanocomposites. The impedance data is observed to gradually enhance with magnetic field due to the strain developed in the sample, hampering the charge flow in the system. The nanocomposites display prominent magneto-impedance (∼87%) and magnetodielectric (∼35%) at room temperature. Nyquist plots are fitted utilizing two resistance-capacitor parallel circuits at varying magnetic fields demonstrating the governing role of La0.7Sr0.3MnO3 and ZnO grain boundaries. The grain boundary resistance of La0.7Sr0.3MnO3 decreases with field due to the depinning of domain walls from the grain boundary pinning centers and therefore improving the spin dependent transport mechanism while the grain boundary resistance of ZnO increases with field due to the scattering of the charge carrier. The magnetoelectric coupling investigated at a frequency of 1 kHz is accomplished in both longitudinal and transverse mode. Further, the magnetoelectric voltage induced by ac magnetic field executes a linear magnetoelectric response. The viewed magnetoelectric coupling might be in consequence of the field influenced magnetostriction of the piezomagnetic element of the composites. Such multiferroic material with tuning ac electrical property with magnetic field alongside magnetoelectric response can be pertinent in future solid-state microelectronic devices and sensor applications.