Room-temperature ferromagnetism in highly-resistive Ni-doped TiO 2

J. H. Cho; T. J. Hwang; Y. G. Joh; E. C. Kim; Dong Ho Kim; K. J. Lee; H. W. Park; H. C. Ri; J. P. Kim; C. R. Cho

doi:10.1063/1.2179607

Room-temperature ferromagnetism in highly-resistive Ni-doped TiO ₂

J. H. Cho, T. J. Hwang, Y. G. Joh, E. C. Kim, Dong Ho Kim, K. J. Lee, H. W. Park, H. C. Ri, J. P. Kim, C. R. Cho

Department of Physics

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49 Scopus citations

Abstract

We investigated the magnetic and transport properties of Ni-doped TiO2 films grown by a sol-gel method with Ni concentrations from 1% to 8%. All the samples exhibited ferromagnetism at room temperature identified by optical magnetic circular dichroism along with magnetometer measurement. The microstructural and compositional analysis revealed Ni-rich regions with rather uniform background, indicating that at least two different sources contribute to the observed ferromagnetism. The Hall effect study showed that the carriers are electrons with density lower than 1018 cm-3 at room temperature, and no anomalous Hall effect has been observed due to the high resistivity of our samples. The observation of ferromagnetism in highly-resistive Ni-doped TiO2 films questions the carrier-mediated exchange interaction as an origin of ferromagnetism in this material.

Original language	English
Article number	092505
Journal	Applied Physics Letters
Volume	88
Issue number	9
DOIs	https://doi.org/10.1063/1.2179607
State	Published - 27 Feb 2006

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title = "Room-temperature ferromagnetism in highly-resistive Ni-doped TiO 2",

abstract = "We investigated the magnetic and transport properties of Ni-doped TiO2 films grown by a sol-gel method with Ni concentrations from 1% to 8%. All the samples exhibited ferromagnetism at room temperature identified by optical magnetic circular dichroism along with magnetometer measurement. The microstructural and compositional analysis revealed Ni-rich regions with rather uniform background, indicating that at least two different sources contribute to the observed ferromagnetism. The Hall effect study showed that the carriers are electrons with density lower than 1018 cm-3 at room temperature, and no anomalous Hall effect has been observed due to the high resistivity of our samples. The observation of ferromagnetism in highly-resistive Ni-doped TiO2 films questions the carrier-mediated exchange interaction as an origin of ferromagnetism in this material.",

author = "Cho, {J. H.} and Hwang, {T. J.} and Joh, {Y. G.} and Kim, {E. C.} and Kim, {Dong Ho} and Lee, {K. J.} and Park, {H. W.} and Ri, {H. C.} and Kim, {J. P.} and Cho, {C. R.}",

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T1 - Room-temperature ferromagnetism in highly-resistive Ni-doped TiO 2

AU - Cho, J. H.

AU - Hwang, T. J.

AU - Joh, Y. G.

AU - Kim, E. C.

AU - Kim, Dong Ho

AU - Lee, K. J.

AU - Park, H. W.

AU - Ri, H. C.

AU - Kim, J. P.

AU - Cho, C. R.

PY - 2006/2/27

Y1 - 2006/2/27

N2 - We investigated the magnetic and transport properties of Ni-doped TiO2 films grown by a sol-gel method with Ni concentrations from 1% to 8%. All the samples exhibited ferromagnetism at room temperature identified by optical magnetic circular dichroism along with magnetometer measurement. The microstructural and compositional analysis revealed Ni-rich regions with rather uniform background, indicating that at least two different sources contribute to the observed ferromagnetism. The Hall effect study showed that the carriers are electrons with density lower than 1018 cm-3 at room temperature, and no anomalous Hall effect has been observed due to the high resistivity of our samples. The observation of ferromagnetism in highly-resistive Ni-doped TiO2 films questions the carrier-mediated exchange interaction as an origin of ferromagnetism in this material.

AB - We investigated the magnetic and transport properties of Ni-doped TiO2 films grown by a sol-gel method with Ni concentrations from 1% to 8%. All the samples exhibited ferromagnetism at room temperature identified by optical magnetic circular dichroism along with magnetometer measurement. The microstructural and compositional analysis revealed Ni-rich regions with rather uniform background, indicating that at least two different sources contribute to the observed ferromagnetism. The Hall effect study showed that the carriers are electrons with density lower than 1018 cm-3 at room temperature, and no anomalous Hall effect has been observed due to the high resistivity of our samples. The observation of ferromagnetism in highly-resistive Ni-doped TiO2 films questions the carrier-mediated exchange interaction as an origin of ferromagnetism in this material.

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JO - Applied Physics Letters

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Room-temperature ferromagnetism in highly-resistive Ni-doped TiO ₂

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