Nature of the reversible paramagnetism to ferromagnetism state in cobalt-doped titanium dioxide

被引：45

作者：

Manivannan, A ^{[1
]}

Glaspell, G ^{[1
]}

Dutta, P ^{[1
]}

Seehra, MS ^{[1
]}

机构：

[1] W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA

来源：

JOURNAL OF APPLIED PHYSICS | 2005年 / 97卷 / 10期

关键词：

D O I：

10.1063/1.1854931

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We report that Co0.1Ti0.9O2-delta prepared by the sol-gel technique is a paramagnet following the Curie-Weiss law: chi=chi(0)+C/(T+theta) with theta similar or equal to 5 K. However, hydrogenation at 673 K in H-2/Ar (5%/95%) gas converts a part of the paramagnetic (P) sample to room temperature ferromagnet (RTFM) and reheating the sample at 573 K in air converts it back to a paramagnet completely. This reversible P reversible arrow RTFM transition has been observed for additional cycles by alternately heating in air and H-2/Ar. It is argued that this RTFM is intrinsic and it is due to Co2+-Co2+ exchange interaction mediated by oxygen holes which are produced by hydrogenation but eliminated by oxidation. (c) 2005 American Institute of Physics.

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