Ferromagnetism in Rutile Structure Cr Doped VO2 Thin Films Prepared by Reactive-Bias Target Ion Beam Deposition

Abstract

First generation spintronics has entered the mainstream of information technology through its utilization of the magnetic tunnel junction in applicable devices such as read head sensors for hard disk drives and magnetic random access memory. The future of spintronic devices requires next generation spintronic materials (Wolf et al. in IBM J. Res. Dev. 9:101, [2006]). Here we report on the structural, transport, and magnetic characteristics of V1−x Cr x O2 (0.1≤x≤0.2) thin films deposited on (001) Al2O3 substrates. We show that the metal-insulator transition of VO2 is suppressed and the rutile structure is stable down to 100 K. The films are remarkably smooth having a root-mean squared surface roughness of 0.3 nm. Films are conductive at room temperature and appear to follow a variable-range-hopping conduction mechanism below that. Ferromagnetism is observed at room temperature and is dependent on Cr concentration. The combination of these characteristics makes V1−x Cr x O2 a viable candidate material for next generation spintronic multilayer devices.