Tuning electrical transport properties in Fe70Ga30/Hf0.5Zr0.5O2 thin films

Abstract

We demonstrate the tunability of electrical transport properties in Fe₇₀Ga₃₀/Hf_0.5Zr_0.5O₂ thin films via both bias voltage and magnetic field. The current–voltage (I–V) characteristics are modulated by applying a bias voltage across the heterojunction thickness, yielding various resistive states. A 5 V bias voltage induces a maximum resistance change of 90% at a scan voltage of 0.9 V, and the device can be switched between high- and low-resistance states for over 100 cycles with a retention time of up to 1.2 × 10⁴ s. Finite element simulations of the non-uniform volumetric strain distribution under applied voltages elucidate the strain coupling effects in the heterojunctions, while experimentally observed oxidation of Fe and Ga reveals the presence of interfacial charge modulation that modifies the transport properties. Based on these findings, we attribute the bias-voltage-modulated transport properties to strain- and charge-co-mediated magnetoelectric effects. Moreover, the I-V behavior is modulated by an external magnetic field through the combined effects of magnetoresistance and interfacial charge effects. We anticipate that this work will inspire research on low-power, high-density thin-film memory devices.