Hall effect and the magnetotransport properties of Co2MnSi1-xAlx Heusler alloys

Prestigiacomo, Joseph; Young, David P.; Adams, P. W.; Stadler, Shane

doi:10.1063/1.4862966

Cited by 39 publications

(25 citation statements)

References 30 publications

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“…A minimum in the resistivity curve was found near 40 K, which was followed by an upturn at lower temperatures. Such a behavior has been reported in many Heusler alloys [84] and is typically attributed to the disorder enhanced coherent scattering of conduction electrons [79]. It was found that for some alloys, such a minimum has been explained on the basis of Kondo effect [85].…”

Section: A Cofemnz (Z = Si and Ge) Alloysmentioning

confidence: 84%

“…In addition to the contributions mentioned above, a term representing the structural disorder with a temperature dependence of T 1/2 is also present in systems with non-negligible disorder [84]. Keeping all the above points in mind, Bainsla et al [7] analyzed the resistivity data by performing the fitting in two different temperature regions, i.e., between 5 and 85 K and between 85 and 300 K. The resistivity trend was found to fit well with the relation, ρ (T) = ρ0 -AT 1/2 + BT 2 + CT 9/2 in the low temperature region, while the best fit is given by ρ (T) = ρ0 + DT + ET 7/ 2 in the high temperature region.…”

Section: A Cofemnz (Z = Si and Ge) Alloysmentioning

confidence: 99%

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Equiatomic quaternary Heusler alloys: A material perspective for spintronic applications

Bainsla

Суреш

2016

Applied Physics Reviews

270

104

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Half-metallic ferromagnetic (HMF) materials show high spin polarization and are therefore interesting to researchers due to their possible applications in spintronic devices. In these materials, while one spin sub band has a finite density of states at the Fermi level, the other sub band has a gap. Because of their high Curie temperature (TC) and tunable electronic been reported in a few systems, which are also discussed in this review. Thus, this review presents a consolidated picture of the magnetic and spintronic properties of this important, but relatively new class of Heusler alloys. It is expected that this will stimulate further interest in these alloys, thereby paving the way for the identification of more HMF and SGS materials. As a result of this, it is expected that more efficient spintronic devices using these alloys would emerge in the near future.

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Section: A Cofemnz (Z = Si and Ge) Alloysmentioning

confidence: 84%

Section: A Cofemnz (Z = Si and Ge) Alloysmentioning

confidence: 99%

Equiatomic quaternary Heusler alloys: A material perspective for spintronic applications

Bainsla

Суреш

2016

Applied Physics Reviews

270

104

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“…While electron-magnon scattering is absent in the case of true halfmetals, T 1/2 dependence reflects the contribution due to the disorder. 28 Fitting of the resistivity data has been carried out in two different temperature regions, i.e., between 5 and 85 K and between 85 and 300 K. In the low temperature region, the resistivity fits well with the relation, ρ (T) = ρ 0 -AT 1/2 + BT 2 + CT 9/2 , while in the high temperature region, the best fit is given by ρ (T) = ρ 0 + DT + ET 7/2 . In the low temperature regime, T 1/2 term dominates over the other two contributions due to the presence of disorder.…”

mentioning

confidence: 99%

“…Heusler alloys 28 and is typically attributed to the disorder enhanced coherent scattering of conduction electrons. 29 Resistivity behavior has been analyzed in the temperature range of 5 -300 K by considering different scattering mechanisms.…”

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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

121

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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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“…Recently, Co-based Heusler alloys have attracted intense attention as potential candidates for spintronic devices due to their high Curie temperature and half-metallic electronic structure [5,27]. Reported AHE studies on Co-based Heusler alloys include bulk, granular film, bilayer, or trilayer systems, such as bulk Co 2 MnSi 1-x Al x [28], Co 2 FeSi-Al 2 O 3 granular films, Co 2 MnAl, Co 2 FeSi, Co 2 FeAl, Co 2 MnGe, and Co 2 MnSi monolayers [6,[29][30][31], Pt/Co 2 FeAl bilayer [32], or MgO/Co 2 MnGa/Pd trilayer [33]. In our previous report, a large PMA was realized in Pd/Co 2 MnSi/MgO trilayer, which was attributed to the interfacial orbital hybridization adjacent to the Heusler alloy Co 2 MnSi layer, namely, Pd/Co 2 MnSi and Co 2 MnSi/MgO interfaces [34].…”

Section: Introductionmentioning

confidence: 99%

Interfacial contributions to anomalous Hall effect in perpendicular magnetic anisotropic [Co2MnSi/Pd]3 multilayer

Chen

et al. 2018

Phys. Rev. Materials

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Through engineering the interface between Co2MnSi and Pd, we realize a high perpendicular magnetic anisotropy (PMA) and controllable anomalous Hall effect (AHE) in [Co2MnSi(tCMS)/Pd]3multilayers. The multilayers are characterized by a particulatelike layer morphology following annealing at 573 K with weak B2 crystallographic ordering of the Co2MnSi layer. The largest PMA (Keff) of 1.2x106erg/cm3 has been obtained in [Co2MnSi(1.2nm)/Pd]3 multilayer annealed at 573 K. The AHE can be tuned, which we attribute to a varying proximity effect at the Co2MnSi/Pd interface, by varying the annealing temperature and Co2MnSi thickness. According to the expanded AHE scaling relation, we calculate the different contributions to the origin of AHE. Both skew scattering and side jump decrease monotonically with increasing Co2MnSi thickness, but show maximum values for the multilayer annealed around 573 K with increasing annealing temperature. It is found that skew scattering (ρss) and side-jump scattering (ρsj) exhibit opposite contributions to the AHE; the skew scattering ρss is larger than the value of side jump ||ρsj||, giving a ρss value of approximately 1.34 μΩ cm and the absolute ||ρsj|| value of 1.1 μΩ cm at 5 K in [Co2MnSi(1.2nm)/Pd]3 multilayer, indicating that the overall AHE originates mostly from the skew scattering.

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Hall effect and the magnetotransport properties of Co2MnSi1-xAlx Heusler alloys

Abstract: Structural and magnetic properties of quaternary Co2Mn1-xCrxSi Heusler alloy thin films

Cited by 39 publications

References 30 publications

Equiatomic quaternary Heusler alloys: A material perspective for spintronic applications

Equiatomic quaternary Heusler alloys: A material perspective for spintronic applications

High spin polarization in CoFeMnGe equiatomic quaternary Heusler alloy

Interfacial contributions to anomalous Hall effect in perpendicular magnetic anisotropic [Co2MnSi/Pd]3 multilayer

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