Spin-resolved density of states at the surface of NiMnSb

Zhu, Wenzhong; Sinković, B.; Vescovo, E.; Tanaka, C. T.; Moodera, Jagadeesh S.

doi:10.1103/physrevb.64.060403

Cited by 64 publications

(45 citation statements)

References 14 publications

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“…2 Several experimental studies on bulk samples including measurements of resistivity, Hall effect, and magnetic properties arrived at the conclusion that the ground state of NiMnSb is half-metallic. 2,3 This was supported by the positron-annihilation measurements of bulk spin-polarization by Hanssen et al 4 In contrast, surface sensitive techniques, such as superconducting point contact measurements ͑Andreev reflection 5 ͒ 6,7 and spin-resolved photoemission spectroscopy 8,9 have failed to reproduce spin-polarization beyond the extent of a normal ferromagnet, even at low temperature. Calculations indicate NiMnSb surfaces and interfaces not to be half-metallic in general but using a suitably chosen interface-such as ͑111͒ oriented CdS or InP-halfmetallicity can be restored.…”

Section: Introductionmentioning

confidence: 76%

Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1−xMn1+xSb

Ekholm

Larsson

Alling

et al. 2010

Journal of Applied Physics

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We perform a combined theoretical and experimental study of the phase stability and magnetism of the off-stoichiometric Ni 1−x Mn 1+x Sb in the half-Heusler crystal phase. Our work is motivated by the need for strategies to engineer the magnetism of potentially half-metallic materials, such as NiMnSb, for improved performance at elevated temperatures. By means of ab initio calculations we investigate Ni 1−x Mn 1+x Sb over the whole composition range 0 Յ x Յ 1 of Ni replacing Mn and show that at relevant temperatures, the half-Heusler phase should be thermodynamically stable up to at least x = 0.20 with respect to the competing C38 structure of Mn 2 Sb. Furthermore we find that half-Heusler Ni 1−x Mn 1+x Sb retains half-metallic band structure over the whole concentration range and that the magnetic moments of substitutional Mn Ni atoms display magnetic exchange interactions an order of magnitude larger than the Ni-Mn interaction in NiMnSb. We also demonstrate experimentally that the alloys indeed can be created by synthesizing off-stoichiometric Ni 1−x Mn 1+x Sb films on MgO substrates by means of magnetron sputtering.

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Section: Introductionmentioning

confidence: 76%

Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1−xMn1+xSb

Ekholm

Larsson

Alling

et al. 2010

Journal of Applied Physics

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“…More recent superconducting/ferromagnetic point contact measurements on a Co 2 MnSi single crystal gave a spin polarization of 55% [47]. Similarly, the degree of spin polarization determined from the analysis of spin resolved photoemission spectra was always found to be definitely below 100% [48,49].…”

Section: Dos (States/ev)mentioning

confidence: 94%

Antiferromagnetic dipolar ordering in[Co2MnGe∕V]Nmultilayers

et al. 2005

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“…High quality films of NiMnSb have been grown, 48,49,50,51,52,53 but they were found not to reproduce the half-metallic character of the bulk. Values of 58% and 50% for the spin-polarization at the Fermi level were obtained by Soulen et al 54 and by Mancoff et al, 55 respectively, and recently Zhu et al 56 found a value of 40% using spin-resolved photoemission measurements on polycrystalline films. Ristoiu et al 57,58,59,60 showed that during the growth of the NiMnSb thin films, Sb atoms segregate to the surface decreasing the obtained spinpolarization; they measured a value of ∼30% at 200K, while at room temperature the net polarization was practically zero.…”

Section: Introductionmentioning

confidence: 92%

Ab initio electronic and magnetic properties of half-metallic NiCrSi and NiMnSi Heusler alloys: The role of defects and interfaces

Galanakis

Özdoğan

Şaşıoğlu

2008

Journal of Applied Physics

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Using state-of-the-art first-principles calculations we study the properties of the ferromagnetic Heusler compounds NiYSi where Y stands for V, Cr or Mn. NiCrSi and NiMnSi contrary to NiVSi are half-metallic at their equilibrium lattice constant exhibiting integer values of the total spin magnetic moment and thus we concentrate on these two alloys. The minority-spin gap has the same characteristics as for the well-known NiMnSb alloy being around ∼1 eV. Upon tetragonalization the gap is present in the density of states even for expansion or contraction of the out-of-plane lattice parameter by 5%. The Cr-Cr and Mn-Mn interactions make ferromagnetism extremely stable and the Curie temperature exceeds 1000 K for NiMnSi. Surface and interfaces with GaP, ZnS and Si semiconductors are not half-metallic but in the case of NiCrSi the Ni-based contacts present spinpolarization at the Fermi level over 90%. Finally, we show that there are two cases of defects and atomic-swaps. The first-ones which involve the Cr(Mn) and Si atoms induce states at the edges of the gap which persists for a moderate-concentration of defects. Defects involving Ni atoms induce states localized within the gap completely destroying the half-metallicity. Based on single-impurity calculations we associate these states to the symmetry of the crystal.

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Spin-resolved density of states at the surface of NiMnSb

Cited by 64 publications

References 14 publications

Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1−xMn1+xSb

Ab initio calculations and synthesis of the off-stoichiometric half-Heusler phase Ni1−xMn1+xSb

Antiferromagnetic dipolar ordering in[Co2MnGe∕V]Nmultilayers

Ab initio electronic and magnetic properties of half-metallic NiCrSi and NiMnSi Heusler alloys: The role of defects and interfaces

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