Molecular-beam epitaxy of the half-Heusler alloy NiMnSb on (In,Ga)As/InP (001)

Bach, P.; Bader, Andreas; Rüster, C.; Gould, C.; Becker, C. R.; Schmidt, G.; Molenkamp, L. W.; Weigand, Wolfgang; Kumpf, Christian; Umbach, E.; Urban, R.; Woltersdorf, Georg; Heinrich, B.

doi:10.1063/1.1594286

Cited by 64 publications

(40 citation statements)

References 12 publications

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“…Recently, high quality films of NiMnSb alloys have been also grown [18,19,20], but they were found to be not half-metallic [21,22]; a maximum value of 58% for the spinpolarisation of NiMnSb was obtained by Soulen et al [21]. These polarisation values are consistent with a small perpendicular magnetoresistance measured for NiMnSb in a spin-valve structure [23], and a superconducting and a magnetoresistive tunnel junction [5].…”

Section: Introductionsupporting

confidence: 73%

Structural and magnetic properties of the (001) and (111) surfaces of the half-metal NiMnSb

Galanakis

Bihlmayer

Blügel

2005

J. Phys.: Condens. Matter

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Structural and magnetic properties of the (001) and (111) Abstract. Using the full potential linearised augmented planewave method we study the electronic and magnetic properties of the (001) and (111) surfaces of the half-metallic Heusler alloy NiMnSb from first-principles. We take into account all possible surface terminations including relaxations of these surfaces. Special attention is paid to the spin-polarization at the Fermi level which governs the spin-injection from such a metal into a semiconductor. In general, these surfaces lose the half-metallic character of the bulk NiMnSb, but for the (111) surfaces this loss is more pronounced. Although structural optimization does not change these features qualitatively, specifically for the (111) surfaces relaxations can compensate much of the spin-polarization at the Fermi surface that has been lost upon formation of the surface.

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Section: Introductionsupporting

confidence: 73%

Structural and magnetic properties of the (001) and (111) surfaces of the half-metal NiMnSb

Galanakis

Bihlmayer

Blügel

2005

J. Phys.: Condens. Matter

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“…There are only a few reports on the deposition of high quality thin films at moderate temperatures ͑230-300°C͒ using methods of growth other than PLD. [7][8][9][10][11] The films exhibit saturation magnetization of 4 B / formula unit at 5 K consistent with the expected half-metallic behavior. In addition, the low coercive field of 2 Oe at room temperature and the low resistivity of 6 ⍀ cm at 5 K exhibited by these films constitute strong evidence for their good quality.…”

mentioning

confidence: 48%

Structural, magnetic, and electrical properties of NiMnSb thin films grown on InSb by pulsed-laser deposition

Gardelis

Androulakis

Giapintzakis

et al. 2004

Applied Physics Letters

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We report the growth of single-phase, stoichiometric polycrystalline thin films of the half-Heusler ferromagnet NiMnSb, predicted to be half-metallic, on single crystal InSb (100) substrates heated at 200°C by pulsed laser deposition. The films exhibit saturation magnetization of 4μB∕formula unit at 5K and coercive fields of 2Oe at 300K indicative of their good structural quality. At low temperatures (T<200K) the system behaves like a Heisenberg ferromagnet as expected for a half-metal, while at T>200K it behaves like an itinerant ferromagnet. The resistivity of the film at 5K is 6μΩcm.

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“…The magnetic nanodisc (thickness 44 nm, diameter 1 µm) was patterned by standard e-beam lithography and ion-milling techniques from an extended film of NiMnSb grown by molecular-beam epitaxy on an InP(001) substrate 29 . A 50-nm-thick Si 3 N 4 cap layer was deposited on top of the disc for protection and a broadband coplanar microwave antenna (300-nm-thick Au) was subsequently evaporated on top of the patterned disc.…”

Section: Methodsmentioning

confidence: 99%

Optimal control of vortex-core polarity by resonant microwave pulses

et al. 2010

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In a vortex-state magnetic nanodisc [1][2][3] , the static magnetization curls in the plane, except in the core region, where it points out of plane 4,5 , either up or down, leading to two possible stable states of opposite core polarity p. Dynamical reversal of p by large-amplitude motion of the vortex core [6][7][8][9] has recently been demonstrated experimentally [10][11][12][13][14] , raising the prospect of practical applications, in particular in magnetic-storage devices 15. Here we demonstrate coherent control of p by singleand double-microwave-pulse sequences, taking advantage of the resonant vortex dynamics in a perpendicular-bias magnetic field 16 . Experimental optimization of the microwave-pulse duration required for switching p also yields information about the characteristic decay time of the vortex core in the largeoscillation regime. This time is found to be less than half the length seen in the small-oscillation regime, suggesting a nonlinear behaviour of magnetic dissipation.Magnetic vortices are topological solitons with rich dynamical properties. The lowest-energy excitation of the vortex ground state is the so-called gyrotropic mode 3 , corresponding to the gyration of the vortex core around its equilibrium position with a frequency in the sub-gigahertz range 17,18 . It is now established experimentally 14 that the excitation of this gyrotropic motion leads to a dynamical distortion of the vortex-core profile, as predicted by micromagnetic simulations and theoretical analysis 8 . This distortion increases with the linear velocity of the vortex core and opposes the core polarity, until the critical velocity V c 1.66γ √ A ex (γ is the gyromagnetic ratio of the magnetic material and A ex its exchange constant) is reached and the vortex-core polarity is reversed 9 . In zero magnetic field, dynamical control of the polarity is difficult owing to the degeneracy of the gyrotropic frequencies associated with opposite polarities p = ±1, which can lead to multiple core switching 7,11 . Still, selective core-polarity reversal is possible using a circularly polarized microwave magnetic field because the sense of the core rotation is linked by a right-hand rule to its polarity 12 . Control of polarity switching can also be achieved by precise timing of non-resonant magnetic-field pulses 13,19 , in a similar fashion as domain-wall propagation in magnetic nanowires 20 . Resonant amplification 21 of the vortex gyrotropic motion enables us to reverse the core polarity with minimum excitation power 12,14,15 , as it enables us to concentrate the energy in a narrow frequency band. In this scheme, the damping ratio is an important parameter because it controls the minimum amplitude of the resonant excitation required to switch the core 9 . Here, it is shown that the damping ratio close to the reversal threshold is significantly larger than that measured in the small-oscillation regime. We associate this with the nonlinear nature of the reversal process 6,8 .

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Molecular-beam epitaxy of the half-Heusler alloy NiMnSb on (In,Ga)As/InP (001)

Cited by 64 publications

References 12 publications

Structural and magnetic properties of the (001) and (111) surfaces of the half-metal NiMnSb

Structural and magnetic properties of the (001) and (111) surfaces of the half-metal NiMnSb

Structural, magnetic, and electrical properties of NiMnSb thin films grown on InSb by pulsed-laser deposition

Optimal control of vortex-core polarity by resonant microwave pulses

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