Abstract

The authors report the transport properties of ferromagnetic Ga0.97 Cr0.03 N films with a Curie temperature of over 900 K. Samples synthesized under conditions that produce the maximum occupancy of Cr atoms on the Ga site (∼90%) and the maximum ferromagnetic moment of ∼0.6 μB Cr (775 °C growth temperature) exhibit a T-14 dependence of resistivity, indicative of Mott [J. Non-Cryst. Solids 1, 1 (1968)] phonon-assisted variable range hopping between deep level defects. The observation of variable range hopping in ferromagnetic films indicates that ferromagnetism results from a double-exchange-type mechanism. Films grown at higher temperatures (>800 °C) show enhanced Cr segregation, properties associated with percolative transport, and very small, if any, ferromagnetic moments.

Original languageEnglish (US)
Article number142105
JournalApplied Physics Letters
Volume89
Issue number14
DOIs
StatePublished - 2006

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transport properties
moments
ferromagnetic films
thin films
ferromagnetism
Curie temperature
electrical resistivity
defects
atoms
temperature

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Electrical transport properties of ferromagnetic Ga xCr 1-xN thin films. / Wu, Stephen Y.; Newman, Nathan.

In: Applied Physics Letters, Vol. 89, No. 14, 142105, 2006.

Research output: Contribution to journalArticle

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AB - The authors report the transport properties of ferromagnetic Ga0.97 Cr0.03 N films with a Curie temperature of over 900 K. Samples synthesized under conditions that produce the maximum occupancy of Cr atoms on the Ga site (∼90%) and the maximum ferromagnetic moment of ∼0.6 μB Cr (775 °C growth temperature) exhibit a T-14 dependence of resistivity, indicative of Mott [J. Non-Cryst. Solids 1, 1 (1968)] phonon-assisted variable range hopping between deep level defects. The observation of variable range hopping in ferromagnetic films indicates that ferromagnetism results from a double-exchange-type mechanism. Films grown at higher temperatures (>800 °C) show enhanced Cr segregation, properties associated with percolative transport, and very small, if any, ferromagnetic moments.

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