Magneto-transport and microstructure of Co2Fe(Ga0.5Ge0.5)/Cu lateral spin valves prepared by top-down microfabrication process

Ikhtiar,; Kasai, S.; Itoh, A.; Takahashi, Y. K.; Ohkubo, T.; Mitani, Seiji; Hono, K.

doi:10.1063/1.4874936

Cited by 43 publications

(15 citation statements)

References 22 publications

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“…These properties have been exploited successfully for technological applications. For example, the half-metallicity in ferromagnetic materials is being used for spintronics applications such as spin injectors 7 , magnetic tunnel junctions 8 , spin valves 9 and spin torque transfer-random access memories 10 ; the zero gap trait in spin gapless semiconductors is being used for studying spin Seebeck effect 11 .…”

Section: Introductionmentioning

confidence: 99%

New quaternary half-metallic ferromagnets with large Curie temperatures

Kundu

Ghosh

Banerjee

et al. 2017

Sci Rep

132

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New magnetic materials with high Curie temperatures for spintronic applications are perpetually sought for. In this paper, we present an ab initio study of the structural, electronic and magnetic properties of Quaternary Heusler compounds CoX′Y′Si where X′ is a transition metal with 4d electrons and Y′ is either Fe or Mn. We find five new half-metallic ferromagnets with spin polarisation nearly 100% with very high Curie temperatures. The variation of Curie temperatures as a function of valence electrons can be understood from the calculated inter-atomic exchange interaction parameters. We also identify a few other compounds, which could be potential half-metals with suitable application of pressure or with controlled doping. Our results reveal that the half-metallicity in these compounds is intricately related to the arrangements of the magnetic atoms in the Heusler lattice and hence, the interatomic exchange interactions between the moments. The trends in the atomic arrangements, total and local magnetic moments, interatomic magnetic exchange interactions and Curie temperatures are discussed with fundamental insights.

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Section: Introductionmentioning

confidence: 99%

New quaternary half-metallic ferromagnets with large Curie temperatures

Kundu

Ghosh

Banerjee

et al. 2017

Sci Rep

132

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“…HMF have applications as spin polarized current sources for current-perpendicular-to-plane giant magnetoresistive (CPP-GMR) devices, [7][8] magnetic tunneling junctions, 9 lateral spin valves, 10 and spin injectors to semiconductors. 11 High values of P were observed at low temperatures for certain Co based alloys such as Co 2 Fe(Ga 0.5 Ge 0.5 ), 3 and Co 2 (Fe 0.4 Mn 0.6 )Si, 9 but a strong degradation in the spin transport properties is observed at room temperature for the devices because the value of P decreases drastically with temperature.…”

Section: -6mentioning

confidence: 99%

High spin polarization and spin splitting in equiatomic quaternary CoFeCrAl Heusler alloy

Bainsla

Mallick

Coelho

et al. 2015

Journal of Magnetism and Magnetic Materials

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“…9,11,18,27 This is the first report on the experimental measurement of the spin polarization in equiatomic quaternary Heusler alloys.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6] Half-metallic ferromagnets (FM) have applications as spin ploraized current sources for magnetic tunneling junctions, 7 current-perpendicular-to-plane giantmagnetoresistive (CPP-GMR) devices, [8][9] spin injectors to semiconductors, 10 and lateral spin valves. 11 Recently reported Co 2 Fe(Ga 0.5 Ge 0.5 ), 3 and Co2(Fe 0.4 Mn 0.6 )Si 7 show rather high spin polarization at room temperature; however, their spin transport properties at room temperature is substantially degraded. Because of this, further exploration of half-metallic…”

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confidence: 99%

High spin polarization in CoFeMnGe equiatomic quaternary Heusler alloy

Bainsla

Суреш

Nigam

et al. 2014

Journal of Applied Physics

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119

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We report the structure, magnetic property and spin polarization of CoFeMnGe equiatomic quaternary Heusler alloy. The alloy was found to exist in the L2 1 structure with considerable amount of DO 3 disorder. Thermal analysis result indicated the Curie temperature is about 711K without any other phase transformation up to melting temperature. The magnetization value was close to that predicted by the Slater-Pauling curve. Current spin polarization of P = 0.70 ± 0.1 was deduced using point contact Andreev reflection (PCAR) measurements. Halfmetallic trend in the resistivity has also been observed in the temperature range of 5 K to 300 K. Considering the high spin polarization and Curie temperature, this material appears to be promising for spintronic applications.Key words: Heusler alloy, Mössbauer spectroscopy, Slater-Pauling rule, Spin Polarization, Half-metal. PACS: 75.50.Bp, 75.30.Cr, 75.47.Np, 76.80.+y, 75.76 The polycrystalline bulk sample of an equiatomic CoFeMnGe (CFMG) alloy was prepared by arc melting of stoichiometric quantities of constituent elements in an inert atmosphere. The ingot was melted several times to increase the chemical homogeneity and the final weight loss was less than 1%. To increase the homogeneity, the as-cast alloy was annealed under vacuum for 14 days at 1073 K and then quenched in cold water. The crystal structure was investigated by x-ray diffraction with Cu K α radiation at room temperature. 57 FeMössbauer spectra at room temperature were recorded using a constant acceleration spectrometer with 25 mCi 57 Co(Rh) radioactive source. The spectrometer was calibrated by using natural iron foil of 25 µm before measuring the sample. The obtained spectra were analyzed using PCMOS-II least-squares fitting program. Curie temperature and the structural transition temperature (if any) were probed by using the differential thermal analysis (DTA)with a heating rate of 20 K min -1 . Magnetization measurements at 3 K and 300 K were performed by using a vibrating sample magnetometer (VSM) attached to a physical property measurement system (PPMS, Quantum design). Current spin polarization measurements were done by using the point contact Andreev reflection (PCAR) technique. 19 Sharp Nb tips prepared by electrochemical polishing were used to make point contacts with the sample.Spin polarization of the conduction electrons was obtained by fitting the normalized conductance G(V)/G n curves to the modified Blonder-Tinkham-Klapwijk (BTK) model. 20 A multiple parameter least squares fitting was carried out to deduce spin polarization (P) using dimensionless interfacial scattering parameter (Z), superconducting band gap (∆) and P as variables. Fig. 1 shows the Rietveld refinement of powder XRD pattern recorded at room temperature. The lattice parameter of the alloy was found to be 5.75 Å, which is in agreement with the earlier reports on CFMG. 14 As one can see, superlattice reflections, (111) and (200), are very weak for this alloy. When Z element is from the same period of the periodic system...

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Magneto-transport and microstructure of Co2Fe(Ga0.5Ge0.5)/Cu lateral spin valves prepared by top-down microfabrication process

Cited by 43 publications

References 22 publications

New quaternary half-metallic ferromagnets with large Curie temperatures

New quaternary half-metallic ferromagnets with large Curie temperatures

High spin polarization and spin splitting in equiatomic quaternary CoFeCrAl Heusler alloy

High spin polarization in CoFeMnGe equiatomic quaternary Heusler alloy

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