Ferromagnetism Induced by Defects in Cr-doped TiO2 Nanopowders

doi:10.3724/SP.J.1077.2013.12773

Journal of Inorganic Materials ›› 2013, Vol. 28 ›› Issue (10): 1098-1102.DOI: 10.3724/SP.J.1077.2013.12773

• Research Paper • Previous Articles Next Articles

Ferromagnetism Induced by Defects in Cr-doped TiO₂ Nanopowders

ZHAO Qian^{1, 2}, WU Ping²

(1. Inner Mongolia Key Laboratory for Utilization of Bayan Obo Multi-Metallic Resources: Elected State Key Laboratory, Department of Applied Physics, School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China; 2. Department of Applied Physics, Institute of Advanced Materials Physics, School of Science, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Tianjin University, Tianjin 300072, China)

Received:2012-12-24 Revised:2013-03-03 Published:2013-10-20 Online:2013-09-18
Supported by:
National Natural Science Fundation(51074112); Tianjin Natural Science Foundation(11JCZDJC22100); Science and Technology Department of Inner Mongolia Autonomous Region (01311005); Innovation Fundation Supported by Inner Mongolia University of Science and Technology(2011NCL003)

Abstract

Abstract: Rutile Ti_1-xCr_xO₂ (x=0, 0.04, 0.08) nanopowders were synthesized by the Sol-Gel method. Magnetic measurements indicate that as-prepared Cr-doped rutile TiO₂ nanopowders exhibit room-temperature ferromagnetism with saturation magnetizations Ms of 0.55×10^-3 and 1.6×10^-3 emu/g, respectively, for samples x=0.04 and 0.08. And their coercive forces H_care 220 and 40 Oe, respectively. The saturation magnetizations Ms increase with increasing Cr doping concentration. Annealed nanopowders in Ar atmosphere are superparamagnetic. The tight scan Cr2p by X-ray photoelectron spectroscopy spectra (XPS) indicates that Cr ions are in the +3 state for all samples. Electron paramagnetic resonance (EPR) spectra indicates that Cr³⁺ ions contribute only to paramagnetism. Based on above analysis, slight ferromagnetism of Cr-doped TiO₂nanopowders at room temperature originates from structural defects introduced by doping Cr ions, where oxygen vacancies play an important role.

Key words: Cr-doped TiO₂ nanopowders, room temperature ferromagnetism, structural defects, oxygen vacancies

CLC Number:

O474
O441

ZHAO Qian, WU Ping. Ferromagnetism Induced by Defects in Cr-doped TiO₂ Nanopowders[J]. Journal of Inorganic Materials, 2013, 28(10): 1098-1102.

References

[1] Dietl T, Ohno H, Matsukura F, et al. Zener model description of ferromagnetism in zinc-blende magnetic semiconductors. Science, 2000, 287(5455): 1019–1022.

[2] Matsumoto Y, Murakami M, Shono T, et al. Room-temperature ferromagnetism in transparent transition metal-doped titanium dioxide. Science, 2001, 291(5505): 854–856.

[3] Janisch R, Gopal P, Spaldin N A. Transition metal-doped TiO2 and ZnO-present status of the ?eld. J. Phys.: Condens Matter., 2005, 17(27): R657–R689.

[4] Hong N H, Ruyter A, Prellier W, et al. Room temperature ferromagnetism in anatase Ti0.95Cr0.05O2 thin ?lms: clusters or not? . Appl. Phys. Lett., 2004, 85(25): 6212–6214.

[5] Wang Z J, Tang J K, Zhang H G, et al. Ferromagnetism in chromium-doped reduced-rutile titanium dioxide thin ?lms. J. Appl. Phys., 2004, 95(11): 7381–7383.

[6] Droubay T, Heald S M, Shutthanandan V, et al. Cr-doped TiO2 anatase: a ferromagnetic insulator. J. Appl. Phys., 2005, 97(4): 046103–1–3.

[7] Osterwalder J, Droubay T, Kaspar T, et al. Growth of Cr-doped TiO2 films in the rutile and anatase structures by oxygen plasma assisted molecular beam epitaxy. Thin Sol. Films, 2005, 484(1/2): 289–298.

[8] Kaspar T C, Heald S M, Wang C M, et al. Negligible magnetism in excellent structural quality CrxTi1-xO2 anatase: contrast with high-TC ferromagnetism in structurally defective CrxTi1-xO2. Phys. Rev. Lett., 2005, 95(21): 217203–1–4.

[9] Kaspar T C, Droubay T, Shutthanandan V, et al. Ferromagnetism and structure of epitaxial Cr-doped anatase TiO2 thin ?lms. Phys. Rev. B, 2006, 73(15): 155327–1–12.

[10] Wang Y X, Liu H, Li Z Q, et al. Role of structural defects on ferromagnetism in amorphous Cr-doped TiO2 ?lms. Appl. Phys. Lett., 2006, 89(4): 042511–1–3.

[11] Zhang X, Wang W H, Li L Y, et al. Effect of oxygen partial pressure on the ferromagnetism of Cr-doped TiO2 ?lms. J. Phys. D: Appl. Phys., 2008, 41(1): 015005–1–5.

[12] Gao G Y, Yao K L , Liu Z L, et al. Magnetism and electronic structure of Cr-doped rutile TiO2 from first-principles calculations. J. Magn. Mag. Mater., 2007, 313(1): 210–213.

[13] Ye L H, Freeman A J. Defect compensation, clustering, and magnetism in Cr-doped anatase TiO2. Phys. Rev. B, 2006, 73(8): 081304–1–4.

[14] Sangaletti L, Mozzati M C, Galinetto P, et al. Ferromagnetism on a paramagnetic host background: the case of rutile TM: TiO2 single crystals(TM = Cr, Mn, Fe, Co, Ni, Cu). J. Phys.: Condens. Matter, 2006, 18(32): 7643–7650.

[15] Liu S H, Hsu H S, Lin C R, et al. Effects of hydrogenated annealing on structural defects, conductivity, and magnetic properties of V-doped ZnO powders. Appl. Phys. Lett., 2007, 90(22): 222505–1–3.

[16] Moulder J F, Stickle W F, Sobol P E. Handbook of X-Ray Photoelectron Spectroscopy (Perkin-Elmer, Eden Prairie, MN). 1992.

[17] Dvoranová D, Brezová V, Mazúr M, et al. Investigations of metal-doped titanium dioxide photocatalysts. Appl. Catal. B: Environ., 2002, 37(2): 91–105.

[18] Amorelli A, Evans Jeffrey C, Rowlands C C, et al. An electron spin resonance study of rutile and anatase titanium dioxide polycrystalline powders treated with transition-metal ions. J. Chem. Soc., 1987, 83(12): 3541–3548.

[19] Coey J M D, Venkatesan M, Stamenov P, et al. Magnetism in hafnium dioxide. Phys. Rev. B, 2005, 72(2): 024450–1–6.

[20] Zhao Q, Wu P, Li B L, et al. Activation of room-temperature ferromagnetism in nonstoichiometric TiO2?δ powders by oxygen vacancies. J. Appl. Phys., 2008, 104(7): 073911–1–5.

Ferromagnetism Induced by Defects in Cr-doped TiO₂ Nanopowders

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