The role of Cr substitution on the ferromagnetic properties of Ga 1-xCr xN

Rakesh Singh; Stephen Y. Wu; H. X. Liu; Lin Gu; David Smith; Nathan Newman

doi:10.1063/1.1843276

The role of Cr substitution on the ferromagnetic properties of Ga _1-xCr _xN

Rakesh Singh, Stephen Y. Wu, H. X. Liu, Lin Gu, David Smith, Nathan Newman

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Abstract

Angular-dependent channeling Rutherford backscattering spectroscopy (c-RBS) has been used to quantify the fraction of Cr atoms on substitutional, interstitial, and random sites in epitaxial Ga1-x Crx N films grown by reactive molecular-beam epitaxy. The morphology of these films and correlation with their magnetic properties has been investigated. Films grown at temperatures below ~750 °C have up to 90% of Cr occupying substitutional sites. Post-growth annealing at 825 °C results in a systematic drop in the fraction of substitutional Cr as well as a fall off in the ferromagnetic signal. The roles of nonsubstitutional Cr in transferring charge from the Cr t2 band and segregation of substitutional Cr in the loss of magnetism are discussed. Overall, these results provide strong microscopic evidence that Cr-doped III-N systems are dilute magnetic semiconductors.

Original language	English (US)
Article number	012504
Pages (from-to)	012504-1-012504-3
Journal	Applied Physics Letters
Volume	86
Issue number	1
DOIs	https://doi.org/10.1063/1.1843276
State	Published - Jan 2005

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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title = "The role of Cr substitution on the ferromagnetic properties of Ga 1-xCr xN",

abstract = "Angular-dependent channeling Rutherford backscattering spectroscopy (c-RBS) has been used to quantify the fraction of Cr atoms on substitutional, interstitial, and random sites in epitaxial Ga1-x Crx N films grown by reactive molecular-beam epitaxy. The morphology of these films and correlation with their magnetic properties has been investigated. Films grown at temperatures below ~750 °C have up to 90% of Cr occupying substitutional sites. Post-growth annealing at 825 °C results in a systematic drop in the fraction of substitutional Cr as well as a fall off in the ferromagnetic signal. The roles of nonsubstitutional Cr in transferring charge from the Cr t2 band and segregation of substitutional Cr in the loss of magnetism are discussed. Overall, these results provide strong microscopic evidence that Cr-doped III-N systems are dilute magnetic semiconductors.",

author = "Rakesh Singh and Wu, {Stephen Y.} and Liu, {H. X.} and Lin Gu and David Smith and Nathan Newman",

note = "Funding Information: This work was supported by the Defense Advanced Research Projects Agency (DARPA) and administered by the Office of Naval Research (Contract No. N00014-02-1-0598). We acknowledge use of facilities in the Center for Solid State Science at ASU. The authors thank Barry Wilkens for his assistance with angular scans. We also thank Art Freeman and Mark van Schilfgaarde for enlightening discussions.",

year = "2005",

month = jan,

doi = "10.1063/1.1843276",

language = "English (US)",

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journal = "Applied Physics Letters",

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AU - Singh, Rakesh

AU - Wu, Stephen Y.

AU - Liu, H. X.

AU - Gu, Lin

AU - Smith, David

AU - Newman, Nathan

N1 - Funding Information: This work was supported by the Defense Advanced Research Projects Agency (DARPA) and administered by the Office of Naval Research (Contract No. N00014-02-1-0598). We acknowledge use of facilities in the Center for Solid State Science at ASU. The authors thank Barry Wilkens for his assistance with angular scans. We also thank Art Freeman and Mark van Schilfgaarde for enlightening discussions.

PY - 2005/1

Y1 - 2005/1

N2 - Angular-dependent channeling Rutherford backscattering spectroscopy (c-RBS) has been used to quantify the fraction of Cr atoms on substitutional, interstitial, and random sites in epitaxial Ga1-x Crx N films grown by reactive molecular-beam epitaxy. The morphology of these films and correlation with their magnetic properties has been investigated. Films grown at temperatures below ~750 °C have up to 90% of Cr occupying substitutional sites. Post-growth annealing at 825 °C results in a systematic drop in the fraction of substitutional Cr as well as a fall off in the ferromagnetic signal. The roles of nonsubstitutional Cr in transferring charge from the Cr t2 band and segregation of substitutional Cr in the loss of magnetism are discussed. Overall, these results provide strong microscopic evidence that Cr-doped III-N systems are dilute magnetic semiconductors.

AB - Angular-dependent channeling Rutherford backscattering spectroscopy (c-RBS) has been used to quantify the fraction of Cr atoms on substitutional, interstitial, and random sites in epitaxial Ga1-x Crx N films grown by reactive molecular-beam epitaxy. The morphology of these films and correlation with their magnetic properties has been investigated. Films grown at temperatures below ~750 °C have up to 90% of Cr occupying substitutional sites. Post-growth annealing at 825 °C results in a systematic drop in the fraction of substitutional Cr as well as a fall off in the ferromagnetic signal. The roles of nonsubstitutional Cr in transferring charge from the Cr t2 band and segregation of substitutional Cr in the loss of magnetism are discussed. Overall, these results provide strong microscopic evidence that Cr-doped III-N systems are dilute magnetic semiconductors.

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The role of Cr substitution on the ferromagnetic properties of Ga _1-xCr _xN

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