23 November 2016

Intrinsic Ferromagnetism in the Diluted Magnetic Semiconductor Co:TiO2

Here we present a study of magnetism in Co0.05Ti0.95O2−δ anatase films grown by pulsed laser deposition under a variety of oxygen partial pressures and deposition rates. Energy-dispersive spectrometry and transmission electron microscopy analyses indicate that a high deposition rate leads to a homogeneous microstructure, while a very low rate or postannealing results in cobalt clustering. Depth resolved low-energy muon spin rotation experiments show that films grown at a low oxygen partial pressure (≈10−6 torr) with a uniform structure are fully magnetic, indicating intrinsic ferromagnetism. First principles calculations identify the beneficial role of low oxygen partial pressure in the realization of uniform carrier-mediated ferromagnetism. This work demonstrates that Co:TiO2 is an intrinsic diluted magnetic semiconductor.
Facility: SμS

Reference: H. Saadaoui et al, Physical Review Letters 117, 227202 (2016)

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