Very Large Magnetoresistance in Lateral Ferromagnetic (Ga,Mn)As Wires with Nanoconstrictions

Rüster, C.; Borzenko, T.; Gould, C.; Schmidt, G.; Molenkamp, L. W.; Liu, X.; Wójtowicz, T.; Furdyna, J. K.; Yu, Zhi; Flatté, Michael E.

doi:10.1103/physrevlett.91.216602

Cited by 156 publications

(120 citation statements)

References 21 publications

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“…A further candidate to explain our observations could be the presence of a domain wall (DW) between differently magnetized regions of the device in the head-to-head and tail-to-tail configuration, which would be absent in the head-to-tail configurations. However, since the constriction is long and the DW would not be strongly geometrically confined, one anticipates only a very low DW resistance in these samples [11,14]. This is confirmed by a comparison of Fig.…”

supporting

confidence: 68%

“…2a and 4a to the occurrence of depletion in the constriction in the sample of Fig. 2a, which drives the transport (in the critical constriction region) into the hopping regime [11]. At the same time, we suggest that in the hopping regime the AMR coefficient changes sign, leading to the observed changes in magnetoresistance.…”

mentioning

confidence: 73%

“…2 are in between the extreme resistance values of the homogeneously magnetized sample. The DW contribution [11] to the constriction resistance can in the present sample thus only be a minor effect on the resistance of the remanent state and does not explain the different resistance levels in Fig. 2.…”

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confidence: 82%

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A non-volatile-memory device on the basis of engineered anisotropies in (Ga,Mn)As

et al. 2007

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Progress in (Ga,Mn)As lithography has recently allowed us to realize structures where unique magnetic anisotropy properties can be imposed locally in various regions of a given device. We make use of this technology to fabricate a device in which we study transport through a constriction separating two regions whose magnetization direction differs by 90• . We find that the resistance of the constriction depends on the flow of the magnetic field lines in the constriction region and demonstrate that such a structure constitutes a non-volatile memory device.

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confidence: 68%

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confidence: 73%

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A non-volatile-memory device on the basis of engineered anisotropies in (Ga,Mn)As

et al. 2007

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“…An important milestone in this field was the discovery of carrier-mediated ferromagnetism in III-V compounds doped with Mn [1]. Intensive efforts have since led to ferromagnetic transition temperatures T C in excess of 150K in (Ga,Mn)As [2,3,4], and an impressive range of prototype devices [5,6,7]. However, for widespread technological usage of these systems, a T C significantly above 300K is necessary, which may yet require the development of new materials.…”

mentioning

confidence: 99%

p -type conductivity in cubic (Ga,Mn)N thin films

Edmonds

Novikov

Sawicki

et al. 2005

Applied Physics Letters

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The electrical and magnetic properties of p-type cubic (Ga,Mn) IntroductionThe emerging field of semiconductor spintronics relies on the ability to manipulate the electron spin in a semiconductor device, thus offering new prospects for non-volatile high speed information storage and processing. An important milestone in this field was the discovery of carrier-mediated ferromagnetism in III-V compounds doped with Mn [1]. Intensive efforts have since led to ferromagnetic transition temperatures T C in excess of 150K in (Ga,Mn)As [2,3,4], and an impressive range of prototype devices [5,6,7]. However, for widespread technological usage of these systems, a T C significantly above 300K is necessary, which may yet require the development of new materials.In this context, the Zener mean-field model prediction of room temperature ferromagnetism in (Ga,Mn) , a value significantly higher than the highest hole concentrations so far obtained in GaN. Furthermore, optical measurements have indicated that the Mn acceptor level lies over 1eV above the valence band maximum in Wurtzite (Ga,Mn)N [9,10], which is in agreement with density-of-states calculations [11]. Therefore, in contrast to the case for (Ga,Mn)As, Mn does not appear to be an efficient acceptor in Wurtzite GaN, and may not be expected to interact strongly with delocalised charge carriers in the conduction or valence bands. In spite of this, there are numerous observations of room temperature ferromagnetism in n-type (Ga,Mn)N, even in cases where no secondary phases have been identified [12]. The origin of the ferromagnetism in these cases is unresolved, but no conclusive evidence for a coupling between magnetic and semiconductor properties has been demonstrated, and it appears that this effect lies outside the Zener model prediction.It may be expected that Mn incorporation is favoured in the metastable zincblende (cubic) phase of GaN, since MnN is itself cubic with a similar lattice constant to GaN. at room temperature [14]. Cubic (Ga,Mn)N may therefore be a more promising candidate than the Wurtzite phase for room temperature carrier-mediated ferromagnetism. It is important to determine the origin of the p-type conductivity and investigate the nature of the Mn state in this material. Here we report on a detailed study of the electrical and magnetic properties of cubic (Ga,Mn)N films grown on GaAs(001) by molecular beam epitaxy. Growth and structureUndoped cubic GaN films and cubic (Ga,Mn)N layers were grown on semi-insulating GaAs (001) substrates by plasma-assisted molecular beam epitaxy (PA-MBE) using arsenic as a surfactant to initiate the growth of cubic phase material [15]. Films where grown under Nrich conditions, which has been found to be necessary for the effective substitutional incorporation of Mn in hexagonal (Ga,Mn)N [16]. The substrate temperature was measured using an optical pyrometer. Growth temperatures from 450 to 680 o C were used. The active nitrogen for the growth of the group III-nitrides was provided by an CARS25 RF activated plasma source...

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“…In each case, charge carriers have to cross either 60º DW or 120º DW at the junction surmounting then an extra resistance associated with the DW. 5,6 Generally, different effects contribute to the DW resistance in a given material. Some of them follow basically from the Lorentz force, 7 others are related to the spin-dependent scattering of charge carriers in the wall.…”

mentioning

confidence: 99%

Magneto-Resistive Memory in Ferromagnetic (Ga, Mn)As Nanostructures

Wosiński¹,

Figielski²,

Andrearczyk³

et al. 2010

AIP Conference Proceedings

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We show a novel magneto-resistive effect that appears in lithographically shaped, three-arm nanostructure, fabricated from ferromagnetic (Ga,Mn)As layers. The effect, related to a rearrangement of magnetic domain walls between different pairs of arms in the structure, reveals as a dependence of zero-field resistance on the direction of previously applied magnetic field. This effect could allow designing devices with unique switching and memory properties. _______________________________ *Electronic

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Very Large Magnetoresistance in Lateral Ferromagnetic (Ga,Mn)As Wires with Nanoconstrictions

Cited by 156 publications

References 21 publications

A non-volatile-memory device on the basis of engineered anisotropies in (Ga,Mn)As

A non-volatile-memory device on the basis of engineered anisotropies in (Ga,Mn)As

p -type conductivity in cubic (Ga,Mn)N thin films

Magneto-Resistive Memory in Ferromagnetic (Ga, Mn)As Nanostructures

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