Multivalued dependence of the magnetoresistance on the quantized conductance in nanosize magnetic contacts

Тагиров, Л. Р.; Vodopyanov, B. P.; Efetov, K. B.

doi:10.1103/physrevb.65.214419

Cited by 45 publications

(38 citation statements)

References 25 publications

(50 reference statements)

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“…9 and 10. According to the quasiclassical theory of spin transport through magnetic nanocontact given by Tagirov et al, 9,10 large MR can be obtained if strong spin scattering at the DW is achieved for antiparallel alignment of magnetization in the magnetic nanocontact. To realize large spin scattering, the electron spin orientation should be preserved during transit through nanocontacts.…”

Section: Gϭgmentioning

confidence: 99%

“…9 Furthermore, Tagirov et al have predicted that the nanocontact of highly spin-polarized metals such as LSMO and CrO 2 would show very large MR of 1000% or higher. 10 The mean free path l of CrO 2 is about 1.4 nm or less at room temperature, and this was derived from theoretical values of Lewis et al 21 The value is very small compared to that of normal metals, which is in the range of a few tens of nanometers. Therefore, diffusive transport seems to be dominant at CrO 2 nanocontacts when l Ͻd.…”

Section: Gϭgmentioning

confidence: 99%

“…Despite differences in formulation, several theories [6][7][8][9][10] suggest that the effect is due to spin scattering at the domain wall and is dependent of the ratio of the spin relaxation length with the domain wall width. Since the domain wall width is a function of the junction area, the effect is consequently a function of the contact area as well.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Universal scaling of magnetoconductance in magnetic nanocontacts (invited)

Muñoz

Garcı́a

et al. 2003

Journal of Applied Physics

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We present results of half-metallic ferromagnets formed by atomic nanocontact of CrO 2 -CrO 2 and CrO 2 -Ni that show as much as 400% magnetoconductance. Analysis of the magnetoconductance versus conductance data for all materials known to exhibit so-called ballistic magnetoresistance strongly suggests that the magnetoconductance of nanocontacts follows universal scaling. If the maximum magnetoconductance is normalized to unity and the conductance is scaled to the resistivity of the material, then all data points fall into a universal curve that is independent of the contact material and the transport mechanism. The analysis was applied to all available magnetoconductance data of magnetic nanocontacts in the literature, and the results agree with theory that takes into account the spin scattering within a magnetic domain wall.

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Section: Gϭgmentioning

confidence: 99%

Section: Gϭgmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Universal scaling of magnetoconductance in magnetic nanocontacts (invited)

Muñoz

Garcı́a

et al. 2003

Journal of Applied Physics

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“…This small effect is due to a strong dependence of MR on the DW thickness. This dependence has been investigated in detail theoretically, [5][6][7][8][9][10] showing that a very narrow DW leads to MR values on the order of 100%. Since DW thickness can be significantly reduced in narrow nanowires, nanoconstrictions, and nanocontacts, significant efforts have been recently devoted to the fabrication and characterization of such nanostructures.…”

mentioning

confidence: 99%

Concept of a nanowire array magnetoresistance device

Shvets

Усов

et al. 2008

Applied Physics Letters

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We describe a concept of the magnetoresistive medium comprising of a planar array of intermingled nanowires with pinned and unpinned magnetic moments. We propose a bottom up method of forming the medium and demonstrate the feasibility of the proposed approach. We present the results of the simulations of the magnetic moments in the nanowires under an external magnetic field to illustrate the concept. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2834371͔Typically a magnetoresistive element consists of separated magnetic pinned ͑PL͒ and free layers ͑FL͒. In these nanostructures, the magnetoresistive effect originates mainly from spin-dependent scattering at the interface between a PL/FL and a nonmagnetic spacer. 1 Alternatively, in magnetic tunneling junctions ͑MTJs͒, spin dependent tunneling through an insulating spacer leads to a large spin asymmetry and correspondingly to magnetoresistance. 2 Such giant magnetoresistance ͑GMR͒ and tunneling magnetoresistance ͑TMR͒ nanoelements are fabricated using a top down lithography-based process, leading to an out-of-plane oriented array of devices commonly operated in the current perpendicular to the plane mode.Recently, increasing attention has been paid to an alternative bulklike mechanism of spin dependent scattering due to domain walls ͑DWs͒ in magnetic nanowires. 3,4 In bulk structures, this mechanism leads to a relatively small magnetoresistive ͑MR͒ effect. This small effect is due to a strong dependence of MR on the DW thickness. This dependence has been investigated in detail theoretically, [5][6][7][8][9][10] showing that a very narrow DW leads to MR values on the order of 100%. Since DW thickness can be significantly reduced in narrow nanowires, nanoconstrictions, and nanocontacts, significant efforts have been recently devoted to the fabrication and characterization of such nanostructures. Typically, such structures are also fabricated using top-down lithographybased nanofabrication techniques. For the present discussion, it is important to note that, overall, the DW scattering mechanism is expected to lead to an order of magnitude smaller MR effect than spin dependent scattering in MTJs or GMR structures.Here, we propose the concept of a magnetoresistive element and fabrication approach which is attractive due to its relative simplicity, as it does not involve multiple lithography steps. Instead, we use the atomic terrace low angle shadowing ͑ATLAS͒ technique, which has the advantage of bottom-up fabrication. We discuss the concept of the MR nanostructure, which utilizes DW scattering where the MR is further enhanced by creating multiple DW's in a nanowire array traversed by the in-plane spin-polarized electron current. Contrary to a conventional approach of single nanowires, we propose using dense array of magnetic wires to stabilize the DW network.The proposed medium consists of a planar array of nanowires with a width of some 5 -50 nm ͑Fig. 1͒. Two types of nanowires are used, the so-called spacer nanowires, marked hatched, and magnetoresistive nan...

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“…[7][8][9] Experiments performed on Ni break junctions showed unexpectedly large magnetoresistance (MR) values that were attributed to a constrained DW. 10 Although the results of these experiments are currently under debate, they stimulated theoretical studies of spin-dependent transport in constrained geometries using both free-electron models [11][12][13][14][15] and ab initio calculations. [16][17][18] In particular, a very abrupt DW was predicted for atomic-size junctions with the characteristic width of a few interatomic distances, which might explain the enhanced DW resistance.…”

mentioning

confidence: 99%

Field-controlled domain-wall resistance in magnetic nanojunctions

Burton

Kashyap

Zhuravlev

et al. 2004

Applied Physics Letters

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The electrical resistance of a constrained domain wall in a nanojunction is investigated using micromagnetic modeling and ballistic conductance calculations. The nanojunction represents two ferromagnetic electrodes connected by a ferromagnetic wire of 10 nm in length and of a few nanometers in cross section. We find that the anisotropy of the electrodes favors a localization of the domain wall within the constriction (wire) revealing a positive domain-wall resistance. An applied magnetic field moves the domain wall toward one of the electrodes and reduces its width. This compression of the domain wall leads to a sizeable enhancement of the domain-wall resistance.

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Multivalued dependence of the magnetoresistance on the quantized conductance in nanosize magnetic contacts

Cited by 45 publications

References 25 publications

Universal scaling of magnetoconductance in magnetic nanocontacts (invited)

Universal scaling of magnetoconductance in magnetic nanocontacts (invited)

Concept of a nanowire array magnetoresistance device

Field-controlled domain-wall resistance in magnetic nanojunctions

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