Synthesis and Magnetodielectric Evaluation of LaMnO₃:rGO Thin Films on Quartz Using Sol–Gel Spin Coating

Abstract

Synergetic effects of lanthanum manganite (LaMnO₃) and reduced graphene oxide (rGO) enhance the electrical, magnetic, and magneto-dielectric properties in thin films for advanced uses in spintronic, sensors, memory devices, energy storage, flexible electronics, and other fields. This work investigates the multiferroic behaviour of LaMnO₃ and LaMnO₃: rGO thin films with 5 wt% and 20 wt% rGO, synthesized via spin coating, maintaining the perovskite structure and yielding uniform 22 nm LaMnO₃ particles embedded in rGO sheets. Dielectric properties were assessed from 100 Hz to 1 MHz, while magnetic properties were analyzed at low (5 K) and room temperature (300 K), revealing spontaneous magnetization. The films showed a maximum magneto-dielectric effect of 17.9% at 10 kOe and high magneto-electric coupling coefficients (γ ≈ -1.85 × 10⁻¹ (memu/g)⁻² and χE ≈ 145.45 mV/cm Oe) in LaMnO₃, demonstrating potential for non-volatile, lead-free multiferroic memory devices due to the coexistence of room-temperature ferroelectric and ferromagnetic orders.