Specific features of the electrical resistance of half-metallic ferromagnetic alloys Co2CrAl and Co2CrGa

Коуров, Н. И.; Lukoyanov, A. V.; Марченков, В. В.

doi:10.1134/s1063783413120172

Cited by 17 publications

(7 citation statements)

References 9 publications

(30 reference statements)

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“…It seems that the observed correlation in the behavior of the dependences of R0(z) and ρ0(z) indicates the essential role of scattering processes of current carriers in the formation of AHE. However, as was shown earlier [6][7][8], the electrical resistivity of the alloys considered is mainly determined by the parameters of the electron spectrum at EF. We can thus conclude that the changes in R0 and ρ0 depend on the number of valence electrons z due to the same reasons, namely, a rearrangement of the electronic band structure near EF.…”

Section: Resultsmentioning

confidence: 88%

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Марченков

Perevozchikova

Коуров

et al. 2018

Journal of Magnetism and Magnetic Materials

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Electrical, magnetic and galvanomagnetic properties of half-metallic Heusler alloys of Co2YZ (Y = Ti, V, Cr, Mn, Fe, Ni, and Z = Al, Si, Ga, Ge, In, Sn, Sb) were studied in the temperature range 4.2-900 K and in magnetic fields of up to 100 kOe. It was found that varying Y in Co2YZ alloys affects strongly the electric resistivity and its temperature dependence ρ(T), while this effect is not observed upon changing Z. When Y is varied, extrema (maximum or minimum) are observed in ρ(T) near the Curie temperature TC. At T ≤ TC, the ρ(T) behavior can be ascribed to a change in electronic energy spectrum near the Fermi level. The coefficients of normal and anomalous Hall effect were determined. It was shown that the latter coefficient, RS, is related to the residual resistivity ρ0 by a power law RS ~ ρ0 k /MS with MS the spontaneous magnetization. The exponent k was found to be 1.8 for Co2FeZ alloys, which is typical for asymmetric scattering mechanisms, and 2.9 for Co2YAl alloys, which indicates an additional contribution to the anomalous Hall effect. The type of the temperature dependence ρ(T) is analyzed and discussed in the frame of two-magnon scattering theory.

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Section: Resultsmentioning

confidence: 88%

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Марченков

Perevozchikova

Коуров

et al. 2018

Journal of Magnetism and Magnetic Materials

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“…Similar behavior is also reported in various half-metallic ferromagnetic Heusler alloys where a region of negative TCR is observed and was explained on the basis of presence of a gap in the electronic spectrum near E F . [28,[33][34][35] It has also been observed that a negative TCR is generally seen in alloys when the electrical resistivity ρ > 1.5µΩ m in the paramagnetic state. [31,32] For CoRuVGa, the resistivity in the paramagnetic state lies in the range of 5.79 to 6.20 µΩ m and thus it fulfills this condition to show anomaly in the resistivity near the Curie temperature.…”

Section: Coruvgamentioning

confidence: 94%

“…[27] The electron-transport behavior in half-metallic ferromagnetic Heusler alloy Co 2 CrGa was found to show a similar behavior as in our system CRVG. [28,29] Be-low the Curie temperature, the change in resistivity is mainly caused by the magnetic contributions. In case of half-metallic ferromagnets, the magnetic contribution to the conductivity is determined by considering two parallel conduction channels for electrons, one with spin-up and the other with spin down and the total magnetic contribution of conductivity can be written as, [30]…”

Section: Transport Propertiesmentioning

confidence: 99%

Experimental and theoretical investigation on the possible half-metallic behaviour of equiatomic quaternary Heusler alloys: CoRuMnGe and CoRuVZ (Z = Al, Ga)

Rani

Bainsla

Суреш

et al. 2019

Journal of Magnetism and Magnetic Materials

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In this report, structural, electronic, magnetic and transport properties of quaternary Heusler alloys CoRuMnGe and CoRuVZ (Z = Al, Ga) are investigated. All the three alloys are found to crystallize in cubic structure. CoRuMnGe exhibits L21 structure whereas, the other two alloys have B2-type disorder. For CoRuMnGe and CoRuVGa, the experimental magnetic moments are in close agreement with the theory as well as those predicted by the Slater-Pauling rule, while for CoRuVAl, a relatively large deviation is seen. The reduction in the moment in case of CoRuVAl possibly arises due to the anti-site disorder between Co and Ru sites as well as V and Al sites. Among these alloys, CoRuMnGe has the highest TC of 560 K. Resistivity variation with temperature reflects the half-metallic nature in CoRuMnGe alloy. CoRuVAl shows metallic character in both paramagnetic and ferromagnetic states, whereas the temperature dependence of resistivity for CoRuVGa is quite unusual. In the last system, ρ vs. T curve shows an anomaly in the form of a maximum and a region of negative temperature coefficient of resistivity (TCR) in the magnetically ordered state. The ab initio calculations predict nearly half-metallic ferromagnetic state with high spin polarization of 91, 89 and 93 % for CoRuMnGe, CoRuVAl and CoRuVGa respectively. In the case of CoRuMnGe, the XRD analysis reveals that the Co and Ru sites are equally probable. Hence, to investigate the electronic properties of the experimentally observed structure, the Co-Ru swap disordered structures of CoRuMnGe alloy are also simulated and it is found that the disordered structures retain halfmetallic nature, high spin polarization with almost same magnetic moment as in the ideal structure. Nearly half-metallic character, high TC and high spin polarization make CoRuMnGe alloy promising for room temperature spintronic applications. arXiv:1903.07265v2 [cond-mat.mtrl-sci]

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“…This drop in resistivity could be due to a change in crystal structure, though there has been no other evidence of such a structural transition. Another possibility is shown in its close resemblance to the behavior seen in cobalt-based half-metallic ferromagnets Co 2 VAl and Co 2 CrGa, which show similar drops in resistivity above a metallic regime but below the Curie temperature [22,23]. The curve was fit in several parts accounting for which interactions are important in the various temperature ranges.…”

Section: Longitudinal Resistivitymentioning

confidence: 93%

Magnetotransport in ferromagnetic Fe$_2$Ge semimetallic thin films

Forbes,

Bhattarai,

Gassen

et al. 2021

Preprint

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Thin films of the ferromagnet Fe 2 Ge were grown via molecular beam epitaxy, and their electrical and magneto-transport properties measured for the first time. X-ray diffraction and vibrating sample magnetometry measurements confirmed the crystalline ferromagnetic Fe 2 Ge phase. The observed high temperature maximum in the longitudinal resistivity, as well as the observed suppression of electron-magnon scattering at low temperatures, point to the presence of strong spin polarization in this material. Measurements of the Hall resistivity, ρ xy , show contributions from both the ordinary Hall effect and anomalous Hall effect, ρ AH xy , from which we determined the charge carrier concentration and mobility. Measurements also show a small negative magnetoresistance in both the longitudinal and transverse geometries. Fe 2 Ge holds promise as a useful spintronic material, especially for its semiconductor compatibility.

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Specific features of the electrical resistance of half-metallic ferromagnetic alloys Co2CrAl and Co2CrGa

Cited by 17 publications

References 9 publications

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Experimental and theoretical investigation on the possible half-metallic behaviour of equiatomic quaternary Heusler alloys: CoRuMnGe and CoRuVZ (Z = Al, Ga)

Magnetotransport in ferromagnetic Fe$_2$Ge semimetallic thin films

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Specific features of the electrical resistance of half-metallic ferromagnetic alloys Co2CrAl and Co2CrGa

Cited by 17 publications

References 9 publications

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Peculiarities of the electronic transport in half-metallic Co-based Heusler alloys

Experimental and theoretical investigation on the possible half-metallic behaviour of equiatomic quaternary Heusler alloys: CoRuMnGe and CoRuVZ (Z = Al, Ga)

Magnetotransport in ferromagnetic Fe$_2$Ge semimetallic thin films

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Experimental and theoretical investigation on the possible half-metallic behaviour of equiatomic quaternary Heusler alloys: CoRuMnGe and CoRuVZ (Z = Al, Ga)