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We propose a random matrix theory describing the influence of a time dependent external field on the average magnetoresistance of open quantum dots. The effect is taken into account in all orders of perturbation theory, and the result is…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 M. G. Vavilov , I. L. Aleiner

We theoretically investigate the angular and spin dependent transport in normal-metal/helical-multiferroic/ferromagnetic heterojunctions. We find a tunneling anisotropic magnetoresistance (TAMR) effect due to the spiral magnetic order in…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Chenglong Jia , Jamal Berakdar

We investigate theoretically the spin-independent tunneling magnetoresistance effect in a graphene monolayer modulated by two parallel ferromagnets deposited on a dielectric layer. For the parallel magnetization configuration, Klein…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 F. Zhai , K. Chang

A model for magnetoresistance in positionally disordered organic materials is presented and solved using percolation theory. The model describes the effects of spin flips on hopping transport by considering the effect of spin dynamics on an…

Disordered Systems and Neural Networks · Physics 2012-05-02 N. J. Harmon , M. E. Flatté

We present a formalism that simultaneously incorporates the effect of quantum tunneling and spin diffusion on spin Hall magnetoresistance observed in normal metal/ferromagnetic insulator bilayers (such as Pt/YIG) and normal…

Mesoscale and Nanoscale Physics · Physics 2016-12-30 Seulgi Ok , Wei Chen , Manfred Sigrist , Dirk Manske

We present a detailed numerical analysis of the effect of a magnetic field on the transport properties of a `small-$N$' one-sided surface disordered wire. When time reversal symmetry is broken due to a magnetic field $B$, we find a strong…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 A. García-Martín , M. Governale , P. Wölfle

Detailed theoretical derivation is given for the tunnel magnetoresistance via phonon-assisted hopping through an impurity chain under small magnetic field and a large bias window. This derivation provides a rigorous basis for the physical…

Strongly Correlated Electrons · Physics 2014-10-14 Yang Song

Despite the fact that the problem of interference mechanism of magnetoresistance in semiconductors with hopping conductivity was widely discussed, most of existing studies were focused on the model of spinless electrons. This model can be…

Disordered Systems and Neural Networks · Physics 2015-06-03 A. V. Shumilin , V. I. Kozub

In hopping magnetoresistance of doped insulators, an applied magnetic field shrinks the electron (hole) s-wave function of a donor or an acceptor and this reduces the overlap between hopping sites resulting in the positive magnetoresistance…

Materials Science · Physics 2015-05-30 Alexandre S. Alexandrov , Valentin A. Dediu , Victor V. Kabanov

The magnetic field dependent localization in a disordered quantum wire is considered nonperturbatively. An increase of an averaged localization length with the magnetic field is found, saturating at twice its value without magnetic field.…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Stefan Kettemann , Riccardo Mazzarello

We report the observation of a giant positive magnetoresistance in millimetre scale hydrogenated graphene with magnetic field oriented in the plane of the graphene sheet. A positive magnetoresistance in excess of 200\% at a temperature of…

Mesoscale and Nanoscale Physics · Physics 2018-04-25 J. Guillemette , N. Hemsworth , A. Vlasov , J. Kirman , F. Mahvash , P. L. Lévesque , M. Siaj , R. Martel , G. Gervais , S. Studenikin , A. Sachrajda , T. Szkopek

We quantize the electromagnetic field in the presence of a static magnetic monopole, within the loop-representation formalism. We find that the loop-dependent wave functional becomes multivalued, in the sense that it acquires a dependence…

High Energy Physics - Theory · Physics 2015-06-26 Lorenzo Leal , Alexander Lopez

We propose a size effect which leads to the negative magnetoresistance in granular metal-insulator materials in which the hopping between two nearest neighbor clusters is the main transport mechanism. We show that the hopping probability…

Condensed Matter · Physics 2007-05-23 X. R. Wang , X. C. Xie

We propose a mechanism for negative isotropic magnetoresistance in the hopping regime. It results from a memory effect encrypted into spin correlations that are not taken into account by the conventional theory of hopping conductivity. The…

Disordered Systems and Neural Networks · Physics 2015-06-18 Oded Agam , Igor L. Aleiner , Boris Spivak

The paramagnetic insulator to ferromagnetic metal transition in Lanthanum manganites and the associated magnetoresistive phenomena is treated by considering the localization due to random hopping induced by slowly fluctuating spin…

Condensed Matter · Physics 2009-10-28 C. M. Varma

We theoretically and numerically show that longitudinal orbital currents in ferromagnets depend on the magnetization direction, which contribute to the anisotropic magnetoresistance (AMR). This orbital contribution to AMR arises from the…

Mesoscale and Nanoscale Physics · Physics 2020-06-24 Hye-Won Ko , Hyeon-Jong Park , Gyungchoon Go , Jung Hyun Oh , Kyoung-Whan Kim , Kyung-Jin Lee

We study the effect of magnetic scattering on transport in a system with strong structural disorder, using exact finite size calculation of the low frequency optical conductivity. At weak electron-spin coupling spin disorder leads to a…

Disordered Systems and Neural Networks · Physics 2009-11-10 Sanjeev Kumar , Pinaki Majumdar

The influence of a magnetic field on the tunneling of an electron out of a confining plane is studied by a path integral method. We map this 3-d problem on to a 1-d one, and find that the tunneling is strongly affected by the field. Without…

Condensed Matter · Physics 2009-10-22 Ping Ao

In models of hopping disorder in the absence of external fields and at the band center, the electrons are less localized in space than the standard exponential Anderson localization. A signature of this anomalous localization is the square…

Disordered Systems and Neural Networks · Physics 2020-05-20 Rafael A. Molina , Victor A. Gopar

It has been observed that the low temperature magnetoresistance behaviour in polycrystalline colossal magnetoresistive (CMR) manganites differ significantly from the single crystals. The polycrystalline samples show large magnetoresistance…

Strongly Correlated Electrons · Physics 2007-05-23 P. Raychaudhuri , P. Taneja , S. Sarkar , A. K. Nigam , P. Ayyub , R. Pinto