Abstract
We have studied Co-doped indium-tin oxide ITO films deposited by magnetron sputtering on fused-quartz substrates under various conditions. We find that the magnetic and electrical transport properties of these films vary strongly with post-growth treatment. In films with more than 8 at. % of Co, we observe irreversible magnetization and an anomalous Hall effect that are likely caused by a mixed magnetic state, with metal-rich nanoclusters within a ITO:Co matrix. Homogeneous films with less than 8 at. % of Co are ferromagnetic at room temperature. Their magnetic behavior is consistent with a bound magnetic polaron percolation model.
Highlights
Diluted magnetic semiconductorDMSoxide systems that show a high-temperature ferromagneticFMbehavior have a great potential in the development of thin-film optoelectronic spin-based devices.1 In recent years, hightemperature FM behavior has been reported for ZnO films doped with Mn,2 for Co- and Fe-doped TiO2 films,3,4 and for indium-tin oxideITOfilms doped with Mn, Ni, and Cr.5–8 There is yet no consensus on how ferromagnetism comes about in DMS oxides
High-temperature annealing of epitaxial TiO2 : Co films grown by pulsed laser deposition seems to remove the metallic Co nanoclusters, existing in as-grown films, and to incorporate magnetic ions into the host matrix, which leads to intrinsic ferromagnetism
We report the observation of roomtemperatureRTferromagnetism in Co-doped ITO thin films
Summary
Diluted magnetic semiconductorDMSoxide systems that show a high-temperature ferromagneticFMbehavior have a great potential in the development of thin-film optoelectronic spin-based devices. In recent years, hightemperature FM behavior has been reported for ZnO films doped with Mn, for Co- and Fe-doped TiO2 films, and for indium-tin oxideITOfilms doped with Mn, Ni, and Cr. There is yet no consensus on how ferromagnetism comes about in DMS oxides. High-temperature annealing of epitaxial TiO2 : Co films grown by pulsed laser deposition seems to remove the metallic Co nanoclusters, existing in as-grown films, and to incorporate magnetic ions into the host matrix, which leads to intrinsic ferromagnetism.. It has more recently been found that annealing, while removing metallic Co nanoclusters from the bulk, promotes their diffusion to the interface between substrate and film in the same system.. Some high magnetic moment values found in DMS oxides are unprecedented and cannot be accounted for by any known ferromagnetic phase.. Some high magnetic moment values found in DMS oxides are unprecedented and cannot be accounted for by any known ferromagnetic phase.11 Understanding magnetism in these materials is a great challenge for basic physics as well as for device applications Some high magnetic moment values found in DMS oxides are unprecedented and cannot be accounted for by any known ferromagnetic phase. Understanding magnetism in these materials is a great challenge for basic physics as well as for device applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
