Effect of Cr-substitution on vanadium dioxide thin films studied by soft X-ray magnetic circular dichroism

Abstract

The tunability of magnetic properties of VO2 has fascinated substantial attention in the first generation of spintronics-related applications such as read head sensors for hard disk drives and magnetic random-access memory. In this work, we focus on Cr doped VO2, V1−xCrxO2(0 ≤ x ≤ 0.3) (VCO) thin films and study the effect of Cr-substitution on the structural, electronic and magnetic properties. The VCO films were deposited on R-sapphire substrates using a pulse laser deposition method. Soft X-ray absorption spectroscopy (XAS) and soft X-ray magnetic circular dichroism (XMCD) studies of VCO thin films were performed to reveal and understand the origin of maTablegnetization and their enhancement with Cr-substitution. The XAS spectra suggest that the valences of V ions are in tetra and pentavalent states and Cr ions in the trivalent state. The XMCD spectra imply that the V and Cr ions are ferromagnetic at room temperature. These results also indicate that the VCO films are in the ferromagnetic insulating state and charge-ordered at the V and Cr sites. These results are consistent with the first principle density functional theory calculations.