Magnetoresistance in Anderson-localized systems

Kamimura, Hiroshi; Kurobe, A.; Takemori, Tadashi

doi:10.1016/0378-4363(83)90615-0

Cited by 24 publications

(16 citation statements)

References 8 publications

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“…4,11,13,15 A positive MR occurs only at higher temperatures, which is also in good agreement with theoretical modeling of the transport properties. 10 The strong positive MR effects observed at 15 K supports the assumption of hopping conductivity at low temperatures and can be explained with a transport mechanism motivated by Kamimura 26 and Kamimura et al, 27 who discussed spin effects in the hopping regime.…”

Section: Resultssupporting

confidence: 57%

Influence of ordered arrangements of cluster chains on the hopping transport in GaAs:Mn/MnAs hybrids at low temperatures

et al. 2011

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Two different arrangements of cluster chains consisting of elongated MnAs nanoclusters were deposited on (111)B-GaAs substrates by selective-area metal-organic vapor-phase epitaxy. This method allows one a controlled positioning of the nanoclusters on the substrate, offering the possibility to investigate the influence of the nanocluster arrangement on the transport properties of granular hybrid structures. Magnetotransport measurements at low temperatures were performed for both cluster-chain arrangements prepared. In contrast to GaAs:Mn/MnAs hybrids with a random cluster distribution, which usually show a negative magnetoresistance at low temperatures, large positive magnetoresistance effects are observed for cluster-chain arrangements at 15 K. Furthermore, the arrangements exhibit a rectifying behavior of the current-voltage characteristics in the presence of an external magnetic field. The magnitude of both effects correlates with the arrangement of the chains on the substrate and can be explained qualitatively by assuming hopping conduction as the dominant transport mechanism.

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Section: Resultssupporting

confidence: 57%

Influence of ordered arrangements of cluster chains on the hopping transport in GaAs:Mn/MnAs hybrids at low temperatures

et al. 2011

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“…9,44 ͑i͒ The MR data are the sum of the positive and negative contributions, (⌬/)ϭ(⌬/) p ϩ(⌬/) n . ͑ii͒ At high magnetic field, the positive contribution dominates the negative MR component which is saturated at this field.…”

Section: Resultsmentioning

confidence: 99%

“…It is not clear how large the effect of transition-metal impurities is in the low-dimensional conductor, but we were first motivated by the existence of the Ni impurities. [31][32][33][34][35][36][37][38][39][40] We have attempted quantitative analysis of the temperature dependence of the zero-field resistivity as well as the magnetoresistance ͑MR͒ with the localization pictures, 9,10,12,[41][42][43][44][45][46] with an additional contribution from the magnetic impurity Ni. The results are rather consistent with the two-dimensional variable-range-hopping ͑VRH͒ model, with the two-dimensional WL under a magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Magnetoresistance of an entangled single-wall carbon-nanotube network

et al. 1998

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The resistivity (T) and magnetoresistance ͑MR͒ (⌬/) of an entangled single-wall carbon-nanotube network are investigated. The temperature dependence of the resistivity shows a negative d/dT from T ϭ4.3-300 K with no resistivity minimum, which is fitted well to the two-dimensional variable-range-hopping ͑VRH͒ "(T)ϭ 0 exp͓(T 0 /T) 1/3 ͔… formula with T 0 ϭ259.2 K. The MR shows a negative H 2 behavior at low magnetic field. At Tр3.8 K and high magnetic field, the negative MR becomes positive. The positive MR tends to be saturated for HϾ10 T. The negative MR with a positive upturn can be decomposed into a positive contribution from the two-dimensional spin-dependent VRH and a negative contribution from the twodimensional weak localization, with some contribution of the Ni impurities in the sample found with the transmission electron microscope and by energy dispersive spectrometer analysis. ͓S0163-1829͑98͒07848-5͔

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“…One further magnetoresistance model considers hopping transport in a system where some sites can be doubly occupied. [45][46][47][48][49][50][51] A similar model has been used to explain magnetoresistance for hopping transport in organic semiconductors. [52][53][54][55] Adding a second electron to an already occupied donor is assumed to require the Hubbard energy U.…”

Section: Discussion Of Other Hopping Magnetoresistance Mechanismsmentioning

confidence: 99%