Mechanism of large magnetoresistance in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mtext>MnSi</mml:mtext><mml:mo>/</mml:mo><mml:mtext>Ag</mml:mtext><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mtext>Co</mml:mtext></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:mtext>MnSi</mml:mtext></mml:mrow></mml:math>devices with current perpendicular to the plane

Sakuraba, Yuya; Izumi, Kaoru; Taku, Iwase; Bosu, S.; Saito, K.; Takanashi, Kōki; Miura, Yoshio; Futatsukawa, K.; Abe, Kazutaka; Shirai, Masamitsu

doi:10.1103/physrevb.82.094444

Cited by 196 publications

(88 citation statements)

References 28 publications

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“…Furthermore, semiconducting 8 and insulating materials can also be synthesized, as well as materials with more exotic properties like superconductors and topological insulators. 9,10 Half-metallic Heusler alloys are useful in magnetic tunnel junctions and spin valves but the high spin polarization [11][12][13][14] of these materials was only demonstrated at low temperatures, although moderately high TMR can be maintained at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Site-specific order and magnetism in tetragonal Mn3Ga thin films

et al. 2013

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Mn 3 Ga bulk material and thin films deposited on several different substrates have been investigated using x-ray and neutron diffraction, x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and electronic structure calculations using density-functional theory with the aim of determining the atomic site occupancy, magnetic moments, and magnetic structure of this tetragonal D0 22 -structure compound. The Mn 3 Ga has close to ideal site occupancy, with Ga on 2a sites and Mn on 2b and 4d sites. The magnetic structure is basically ferrimagnetic, with the larger Mn moment of about 3 μ B on the 2b site, which is coordinated by 8 Mn 4d and 4 Ga, and the smaller one on the 4d site, which is coordinated by 4 Mn 2b, 4 Ga, and 4 Mn 4d. The Mn d-band occupancy is close to 5 on both sites, and the orbital moments are small, <0.2 μ B . The material nevertheless exhibits substantial uniaxial anisotropy, K u = 1.0 MJ m −3 , which originates from the 4d site. The 2b site has hard axis anisotropy, which together with an oscillatory exchange coupling from the first and second nearest neighbors, leads to a soft component of the magnetization in the c plane, coexisting with c-axis hysteresis loops exhibiting coercivity of up to 1.2 T, and magnetization in the range 110-220 kA m −1 at room temperature, depending on preparation conditions. Tetragonal Mn 2 Ga films behave similarly. Manganese is lost from both sites, but the films have substantially larger magnetization (480 kA m −1 ) and anisotropy constant (2.35 MJ m −3 ) than Mn 3 Ga.

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Section: Introductionmentioning

confidence: 99%

Site-specific order and magnetism in tetragonal Mn3Ga thin films

et al. 2013

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“…The high spin polarization of cubic L2 1 Heusler alloys such as Co 2 MnSi, Co 2 MnGe, and Co 2 Fe(Ge 0.5 Ga 0.5 ) has been used to improve spin transfer toque efficiency, and it leads to high magnetoresistance ratios in both SVs and MTJs. [7][8][9][10][11][12][13] Recently, there has been growing interest in manganesebased compounds with the tetragonal D0 22 structure, which can be regarded as a severely distorted variant of the cubic L2 1 structure. 14,15 Alloys in the Mn 3Àx Ga series with 0 x 1 exhibit uniaxial anisotropy, and density-functional calculations indicate a high spin polarization.…”

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confidence: 99%

Magnetic and electronic properties of D22-Mn3Ge (001) films

Baâdji¹,

Rode²,

Venkatesan³

et al. 2012

Applied Physics Letters

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Oriented thin films of Mn3Ge with the tetragonal D022 structure, grown on strontium titanate substrates, exhibit a low magnetization Ms = 73 kA m−1 combined with high uniaxial anisotropy Ku = 0.91 MJ m−3 at 300 K, making them potentially useful for thermally stable sub-10 nm spin torque memory elements. The highly ordered epitaxial Mn3Ge (001) films show 46% diffusive spin polarization at the Fermi level, measured by point contact Andreev reflection. Density functional calculations show that the compounds are ferrimagnetic, with anisotropic spin polarization at the Fermi level.

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“…[1][2][3] The demand of higher areal density exceeding 2 Tbit/in 2 in hard disc drives (HDDs) highlights current-perpendicularplane (CPP)-GMR devices as a potential successor of the present tunneling magnetoresistive (TMR) device for next generation read head sensors due to its intrinsically low resistance area product (RA) for higher frequency responses. [4][5][6][7] Recently, substantial large MR ratios at room temperature (RT) were realized in fully epitaxial CPP-GMR devices with the usage of the Co-based Heusler alloys such as Co 2 MnSi (CMS), 8 Co 2 Mn(Ga 0.25 Ge 0.75 ) (CMGG), 9 Co 2 (Fe 0.4 Mn 0.6 )Si (CFMS), 10 and Co 2 Fe(Ga 0.5 Ge 0.5 ) (CFGG). 11 Such a high MR output in a low resistance device has already satisfied the MR performance required for the areal density of 2 Tbit/in 2 according to the simulation by Takagishi et al 7 However, all of these high MR outputs have only been demonstrated for the epitaxial CPP-GMR pseudospin-valves (PSVs) grown on unpractical MgO single crystalline substrates, which are too expensive for mass production and incompatible with the current semiconductor industry processes.…”

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confidence: 99%