Cobalt-Doped Anatase TiO2: A Room Temperature Dilute Magnetic Dielectric Material
Structural and magnetic properties of epitaxial CoxTi₁-xO₂ films with x~2%, grown by RF magnetron sputtering from composite oxide targets on lattice matched LaAIO₃(001) substrates have been investigated. The films were sputtered at a deposition rate of ~0.12 Å/s for a range of substrate temperatures from 300°C to 750°C, followed by UHV annealing for 1 hr at 400°C and aging in air for 3 months. XRD experiments determine the best quality of highly oriented anatase (991) phase in films deposited 500-750°C. Magnetic hysteresis loops at 5K and 300K and thermoremanence measurements from 5-365 K show ferromagnetism in all samples in the whole temperature range. Annealing and aging lead to an increase of spontaneous moment an order of magnitude of up to ~1.1 µB/ Co atom at 300 K. As=deposited, annealed, and aged films were found to be highly resistive changes both in surface morphology and distribution of spontaneous magnetization in the annealed films. Possible mechanisms of the ferromagnetic behavior of such dielectric transition metal-doped oxides will be discussed.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15016608
- Report Number(s):
- PNNL-SA-45251; JAPIAU; 6910; KP1704020; TRN: US200515%%281
- Journal Information:
- Journal of Applied Physics, 97:10D320, Vol. 97, Issue 10; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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