Near-complete spin polarization in atomically-smooth chromium-dioxide epitaxial films prepared using a CVD liquid precursor

Anguelouch, A.; Gupta, Arunava; Xiao, Gang; Abraham, David W.; Ji, Yi; Ingvarsson, Snorri; Chien, C. L.

doi:10.1103/physrevb.64.180408

Cited by 123 publications

(80 citation statements)

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“…The system we study is based on cold pressed powders of CrO 2 and MgB 2 mixture, with the percolation path arising through contacts between individual nanoparticles. The two materials are well suited for this experiment: CrO 2 is a half-metallic ferromagnet where the conduction band is fully spin polarized [12][13][14][15][16], whereas MgB 2 is a superconductor with a relatively high bulk critical temperature of 39K. We …nd that the interface conduction between CrO 2 and MgB 2 particles is strongly suppressed compared to that of CrO 2 /CrO 2 or MgB 2 /MgB 2 interfaces, especially below the superconducting transition [17].…”

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confidence: 99%

Double Percolation Transition in Superconductor-Ferromagnet Nanocomposites

et al. 2010

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A double percolation transition is identi…ed in a binary network composed of nanoparticles of MgB 2 superconductor and CrO 2 half-metallic ferromagnet. Anomalously high-resistance or insulating state, as compared to the conducting or superconducting states in single-component systems of either constituent, is observed between two distinct percolation thresholds. This double percolation e¤ect, which is especially pronounced at liquid helium temperatures, is controlled by composite volume fraction and originates from the suppressed interface conduction and tunneling between nanoparticles of di¤erent species. We investigate the scaling behavior near both percolation thresholds, and determine the distinct critical exponents associated with two di¤erent types of transitions.

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confidence: 99%

Double Percolation Transition in Superconductor-Ferromagnet Nanocomposites

et al. 2010

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“…Of all of the half-metallic ferromagnetic materials, CrO 2 is presently the only material with experimentally proven spin polarization close to 100% as measured Andreev reflection. 4,5 These results are motivation to use this material in spintronics devices such as magnetic field sensing and information storage.…”

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confidence: 99%

Bulk and surface physical properties of a CrO2 thin film prepared from a Cr8O21 precursor

Iwai

Muraoka

Wakita

et al. 2010

Journal of Applied Physics

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We have prepared a CrO 2 thin film by chemical vapor deposition from a Cr 8 O 21 precursor and studied the bulk and surface physical properties. The CrO 2 thin film is grown on a TiO 2 ͑100͒ substrate by heating of a Cr 8 O 21 precursor and TiO 2 ͑100͒ substrate together in a sealed quartz tube. The prepared film is found from x-ray diffraction analysis to be an ͑100͒-oriented single phase. The magnetization and resistivity measurements indicate that the film is a ferromagnetic metal with a Curie temperature of about 400 K. Cr 3s core-level and valence band photoelectron spectroscopy spectra reveal the presence of a metallic CrO 2 in the surface region of the film. Our work indicates that preparation from a Cr 8 O 21 precursor is promising for obtaining a CrO 2 thin film with the metallic surface.

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“…The material CrO 2 belongs to the class of half-metallic ferromagnets (HMF), 1,2 as revealed by electronic band structure calculations 3,4 and point contact Andreev spectroscopy (PCAS), [5][6][7] i.e., it has a gap in the minority-spin density of states (DOS) (N ↓ ) at the Fermi level of the order of 1.5 eV, but no gap in the majority DOS (N ↑ ), resulting in complete spin polarization at the Fermi level. These findings have stimulated the interest in CrO 2 as a source of spin-polarized electrons for spintronics devices.…”

Section: Introductionmentioning

confidence: 99%

Anomalous transport in half-metallic ferromagnetic CrO2

Anwar

Aarts

2013

Phys. Rev. B

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We have investigated the transport properties of CrO 2 thin films deposited on TiO 2 and sapphire substrates and find subtle differences with respect to earlier reports. The films are good metals down to low temperatures, with residual resistivities of the order of 6 μ cm for films deposited on TiO 2 and two times higher for films on sapphire substrates. Magnetoresistance (MR) measurements in high fields show an as yet unobserved nonmonotonic behavior, which is particularly pronounced around the sign change that takes place from negative to positive at a temperature around 100 K. Moreover, both the ordinary and anomalous Hall coefficients show considerable changes around 100-150 K, suggesting a change in carrier density together with the onset of the influence of spin defects in this temperature window. At lower temperatures, the MR is a linear function of the applied field, which can be explained as intergrain tunneling MR. This interpretation is also suggested by the angular MR. Planar Hall effect measurements reveal that the CrO 2 thin films are not in a single magnetic domain state even for films deposited on an isostructural TiO 2 substrate.

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Near-complete spin polarization in atomically-smooth chromium-dioxide epitaxial films prepared using a CVD liquid precursor

Cited by 123 publications

References 10 publications

Double Percolation Transition in Superconductor-Ferromagnet Nanocomposites

Double Percolation Transition in Superconductor-Ferromagnet Nanocomposites

Bulk and surface physical properties of a CrO2 thin film prepared from a Cr8O21 precursor

Anomalous transport in half-metallic ferromagnetic CrO2

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