Magnetic and transport properties of Mn3−xGa/MgO/Mn3−xGa magnetic tunnel junctions: A first-principles study

Bai, Zijian; Cai, Yongqing; Shen, Lei; Yang, Ming; Ko, V.; Han, Guchang; Feng, Yuanping

doi:10.1063/1.3676195

Cited by 51 publications

(22 citation statements)

References 27 publications

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“…Manganese (Mn)-based compounds such as manganese-gallium (Mn-Ga), [8][9][10][11][12][13][14][15][16] manganese-cobalt-gallium (Mn-Co-Ga), 17,18 manganese-aluminum (Mn-Al), 19,20 and manganese-aluminum-germanium (Mn-Al-Ge) 21 have been recently studied as potential STT-MRAM materials. As these materials possess tetragonal crystal structures, which give a uniaxial magnetic anisotropy in the c-axis, a perpendicular magnetic anisotropy is generated in (001)-oriented films.…”

Section: Magnetic Properties Of Ultrathin Tetragonal Heuslermentioning

confidence: 99%

Magnetic properties of ultrathin tetragonal Heusler D22-Mn3Ge perpendicular-magnetized films

Sugihara

Suzuki

Miyazaki

et al. 2015

Journal of Applied Physics

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We investigated the crystal structure and magnetic properties of Manganese-germanium (Mn 3 Ge) films having the tetragonal D0 22 structure, with varied thicknesses (5-130 nm) prepared on chromium (Cr)-buffered single crystal MgO(001) substrates. A crystal lattice elongation in the in-plane direction, induced by the lattice mismatch between the D0 22 -Mn 3 Ge and the Cr buffer layer, increased with decreasing thickness of the D0 22 -Mn 3 Ge layer. The films exhibited clear magnetic hysteresis loops with a squareness ratio close to unity, and a step-like magnetization reversal even at a 5-nm thickness under an external field perpendicular to the film's plane. The uniaxial magnetic anisotropy constant of the films showed a reduction to less than 10 Merg/cm 3 in the small thickness range ( 20 nm), likely due to the crystal lattice elongation in the in-plane direction. V C 2015 AIP Publishing LLC. [http://dx.

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Section: Magnetic Properties Of Ultrathin Tetragonal Heuslermentioning

confidence: 99%

Magnetic properties of ultrathin tetragonal Heusler D22-Mn3Ge perpendicular-magnetized films

Sugihara

Suzuki

Miyazaki

et al. 2015

Journal of Applied Physics

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“…Mn-based alloys such as Mn-Ga, [7][8][9][10][11][12][13][14][15] Mn-Co-Ga, 16,17 Mn-Al, 18,19 and Mn-Al-Ge, 20 which possess tetragonal crystal structures have been studied as candidates for STT-MRAM and exhibited low M s , low a, and high K u . Of these alloys, the Mn-Ga system has been studied the most intensively, exhibiting M s % 200-600 emu/cm 3 , 10 a % 0.008-0.015, 10 K u % 10-23.5 Merg/cm 3 , 8,10 and P % 40-58%.…”

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confidence: 99%

High perpendicular magnetic anisotropy in D22-Mn3+xGe tetragonal Heusler alloy films

Sugihara¹,

Mizukami²,

Yamada³

et al. 2014

Applied Physics Letters

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We prepared D022-Mn3+xGe (−0.67 ≤ x ≤ 0.35) epitaxial thin films on MgO(001) substrates with Cr(001) buffer layers and systematically investigated the dependence of their perpendicular magnetic anisotropy constant, saturation magnetization, coercivity, and tetragonal axial ratio (c/a) on their composition and substrate temperature. Single-phase D022 crystal structures were formed in films with compositions of 0 ≤ x ≤ 0.35, prepared at 400 °C. The D022-Mn3Ge films exhibited perpendicular magnetization with a magnetic squareness close to unity. Performing magnetic torque measurements at an applied field of 140 kOe, we estimated a perpendicular magnetic anisotropy constant of 11.8 ± 0.5 Merg/cm3, the highest and the most reliable value yet reported.

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“…Mn 3 Ga and related alloys appear as promising materials in the realization of switching type spin-transfertorque mangnetoresistive random access memories (STTMRAMs). Mn-Ga films present perpendicular magneto anisotropy (PMA) and a nearly compensated ferrimagnetic phase [2][3][4][5][6] . These characteristics are important for the reduction of the switching current and downscaling of the dimensions while maintaining thermal stability in STT-MRAM devices 7 .…”

mentioning

confidence: 99%

Investigation of the Mn3−δGa/MgO interface for magnetic tunneling junctions

ViolBarbosa

Ouardi

Kubota

et al. 2014

Journal of Applied Physics

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The Mn 3 Ga Heusler compound and related alloys are the most promising materials for the realization of spintransfer-torque switching in magneto tunneling junctions. Improved performance can be achieved by high quality interfaces in these multilayered structured devices. In this context, the interface between Mn 1.63 Ga and MgO is of particular interest because of its spin polarization properties in tunneling junctions. We performed a chemical characterization of the MgO/Mn 1.63 Ga junction by hard x-ray photoelectron spectroscopy. The experiment indicated the formation of Ga-O bonds at the interface and evidenced changes in the local environment of Mn atoms in the proximity of the MgO film. In addition, we show that the insertion of a metallic Mg-layer interfacing the MgO and Mn-Ga film strongly suppresses the oxidation of gallium.PACS numbers: 79.60. Jv, 79.60.Dp, 75.30.Gw, 75.70.AkThe engineering of a high performance magnetic tunneling junction (MTJ) is crucial for the emergence of a new class of non-volatile memories and spintronic devices. Directly related with these recent technologies, Mn 2 YZ Heusler compounds, where Y is a transition metal and Z is a main group element, have shown interesting properties such as high spin polarization, high Curie temperature (Tc), low net magnetic moment, and strong magneto-crystalline anisotropy 1 . Mn 3 Ga and related alloys appear as promising materials in the realization of switching type spin-transfertorque mangnetoresistive random access memories (STTMRAMs). Mn-Ga films present perpendicular magneto anisotropy (PMA) and a nearly compensated ferrimagnetic phase 2-6 . These characteristics are important for the reduction of the switching current and downscaling of the dimensions while maintaining thermal stability in STT-MRAM devices 7 . The full understanding and control of growth properties of the Mn-Ga/MgO system will open up avenues for the exploitation of Heusler compounds in ultra-high density memory technologies.The performance of MTJ devices is strongly influenced by the quality of the film interfaces. Long-range ordering of the two-dimensional interfaces is required for conservation of the electron moment transverse to the tunneling current propagation (k ).8 The integration of Heusler compounds in MTJs has been successfully demonstrated for Co 2 MnSi 9,10 . The great advantage of the Mn 2 YZ family over other Heuslers is the tetragonal distortion of the crystalline structure leading to the PMA. This allows an unique combination of high-spin polarization with perpendicular magnetization in MTJs. Recent studies on the engineering of MTJs using Mn-Ga alloys by Kubota et a) Electronic mail: carlos.barbosa@cpfs.mpg.de al. 4,11,12 resulted in the optimized layered structure: Cr buffer/Mn-Ga/MgO/CoFe. The MgO grows compressed on the Mn-Ga structure with a lattice mismatch of approximately 7%4 , which can cause lattice dislocations reducing the crystalline ordering. An insertion of a 4Å metallic Mg layer interfacing MgO and Mn-Ga promotes a slight increase of the ...

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Magnetic and transport properties of Mn3−xGa/MgO/Mn3−xGa magnetic tunnel junctions: A first-principles study

Cited by 51 publications

References 27 publications

Magnetic properties of ultrathin tetragonal Heusler D22-Mn3Ge perpendicular-magnetized films

Magnetic properties of ultrathin tetragonal Heusler D22-Mn3Ge perpendicular-magnetized films

High perpendicular magnetic anisotropy in D22-Mn3+xGe tetragonal Heusler alloy films

Investigation of the Mn3−δGa/MgO interface for magnetic tunneling junctions

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