Bipolar magnetic semiconducting behavior in VNbRuAl

Nag, Jadupati; Rani, Deepika; Kangsabanik, Jiban; Singh, Durgesh; Venkatesh, R.; Babu, P. D.; Суреш, К. Г.; Alam, Aftab

doi:10.1103/physrevb.104.134406

Cited by 17 publications

(12 citation statements)

References 40 publications

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“…There exist three non-degenerate crystal configurations for any equi-atomic quaternary Heusler structure. 17 These are discussed in theoretical results section, which confirm Type-I to be the energetically most stable configuration. Figure S9 shows Rietveld refined (χ 2 = 0.5) synchrotron XRD (SXRD) pattern (using λ = 0.6525 Å) at RT, where Type-I configuration with 12.5% disorder between Co-V (X-Y) and 12.5% disorder between Fe-V (X -Y) atoms is considered for fitting.…”

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confidence: 75%

CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications

Nag,

Rani,

Singh

et al. 2021

Preprint

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We report a combined theoretical and experimental study of a novel quaternary Heusler system CoFeVSb from the view point of room temperature spintronics and thermoelectric applications. It crystallizes in cubic structure with small DO3-type disorder. The presence of disorder is confirmed by room temperature synchrotron X-ray diffraction(XRD) and extended X-ray absorption fine structure (EXAFS) measurements. Magnetization data reveal high ordering temperature with a saturation magnetization of 2.2 µB/f.u. Resistivity measurements reflect half-metallic nature. Double hysteresis loop along with asymmetry in the magnetoresistance(MR) data reveals room temperature spin-valve feature, which remains stable even at 300 K. Hall measurements show anomalous behavior with significant contribution from intrinsic Berry phase. This compound also large room temperature power factor (∼ 0.62 mWatt/m/K 2 ) and ultra low lattice thermal conductivity (∼ 0.4 W/m/K), making it a promising candidate for thermoelectric application. Ab-initio calculations suggest weak half-metallic behavior and reduced magnetization (in agreement with experiment) in presence of DO3 disorder. We have also found an energetically competing ferromagnetic (FM)/antiferromagnetic (AFM) interface structure within an otherwise FM matrix: one of the prerequisites for spin valve behavior. Coexistence of so many promising features in a single system is rare, and hence CoFeVSb gives a fertile platform to explore numerous applications in future.

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confidence: 75%

CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications

Nag,

Rani,

Singh

et al. 2021

Preprint

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“…The intrinsic anomalous Hall conductivity (σ int AHE ) was estimated by integrating the Berry curvature [−Ω z ( k )] over the entire Brillouin zone considering a k -grid of 40 × 40 × 40 with adaptive refinement k -mesh size of 5 × 5 × 5. To capture the effect of disorder in the L2 1 structure, a 64-atom special quasi-random structure (SQS) was generated using Alloy Theoretic Automated Toolkit (ATAT) as described previously …”

Section: Computational Detailsmentioning

confidence: 99%

Topological Spin Semimetal Feature in a Fully Compensated Ferrimagnet CoRuVSi

Nag,

Venkatesh,

Jha

et al. 2023

ACS Appl. Electron. Mater.

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We have identified the quaternary Heusler alloy, CoRuVSi, as a new member of the recently discovered spin semimetals class through experimental and theoretical studies. At room temperature, CoRuVSi crystallizes in a cubic structure with partial L2 1 -type disorder according to synchrotron X-ray diffraction analysis. Magnetization data suggest a small net moment of ∼0.13 μ B (f.u.) −1 , attributed to the disorder, with no clear magnetic ordering at low temperatures. Electrical resistivity measurements provide compelling evidence of semimetallicity dominated by two-carrier conduction, while magnetoresistance data reveal a positive, sublinear, and nonsaturating behavior. Point-contact Andreev reflection spectra show a spin polarization of ∼50%, in good agreement with the simulated results. Furthermore, CoRuVSi exhibits a high thermopower factor of 0.7 mW m −1 K −2 at room temperature. Our ab initio simulations not only confirm the unique semimetallic nature of the material but also reveal a linear band crossing at ∼0.4 eV below the Fermi level due to band inversion, as well as topological nontrivial features of the band structure corroborated with the simulated Berry curvature, intrinsic anomalous Hall conductivity, and the Fermi surface. We have used a special quasi-random structure to simulate the partial L2 1 disorder, which plays a key role in correctly explaining the magnetism and anomalous Hall effect. The simulated anomalous Hall conductivity values for the fully and partially ordered structures are found to be 102 and 52 S (cm) −1 , respectively, with the latter in fairly good agreement with the experimentally measured value of 45 S (cm) −1 . The coexistence of these intriguing properties within a single material offers valuable insights for identifying other potential materials belonging to the same class using a similar strategy.

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“…Heusler alloys are known to exhibit exotic phenomena as well as novel potential applications, which have stimulated a tremendous interest in physics and materials technology. Many systems from this family are reported to be promising spintronic materials such as half-metals (HM) [1] spin gapless semiconductors (SGS), [2] bipolar magnetic semiconductors (BMS), [3] spin-valve [4] etc. Most of the reported Heusler materials are superior to other materials from the application point of view because of their stable structure and high spin-polarization.…”

Section: Introductionmentioning

confidence: 99%

CoRuVSi: A potential candidate for spin semimetal with promising spintronic and thermoelectric properties

Nag¹,

Venkatesh²,

Jha³

et al. 2023

Preprint

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Based on our experimental and theoretical studies, we report the identification of the quaternary Heusler alloy, CoRuVSi as a new member of the recently discovered spin semimetals class. Spin polarised semimetals possess a unique band structure in which one of the spin bands shows semimetallic nature, while the other shows semiconducting/insulating nature. Our findings show that CoRuVSi possesses interesting spintronic and thermoelectric properties. It crystallizes in perfect cubic structure with a partial L21-type disorder at room temperature. Magnetization data reveal a weak ferri-/antiferro magnetic ordering at low temperatures, with only a very small moment ∼ 0.13 µB/f.u., attributed to the disorder. Transport results provide strong evidence of semimetallicity dominated by two-band conduction, while magnetoresistance data show a non-saturating, linear, positive, magnetoresistance. Spin polarization measurements using point-contact Andreev reflection spectra reveal a reasonably high spin polarization of ∼ 50%, which matches fairly well with the simulated result. Furthermore, CoRuVSi shows a high thermopower value of 0.7 mW att/m − K 2 at room temperature with the dominant contribution from the semimetallic bands, rendering it as a promising thermoelectric material as well. Our ab-initio simulation not only confirms a unique semimetallic feature, but also reveals that the band structure hosts a linear band crossing at ∼ -0.4 eV below the Fermi level incorporated by a band-inversion. In addition, the observed topological non-trivial features of the band structure is corroborated with the simulated Berry curvature, intrinsic anomalous Hall conductivity and the Fermi surface. The partial L21 disorder is simulated using a special quasi random structure, which plays a crucial role in correctly explaining the magnetism and anomalous Hall effect. The simulated anomalous Hall conductivity for ordered and L21 disordered phase of CoRuVSi is found to be 102 and 52 S/cm, the later agrees fairly well with the experimentally measured value (45 S/cm). The coexistence of many interesting properties relevant for spintronic, topological and thermoelectric applications in a single material is extremely rare and hence this study could promote a similar strategy to identify other potential materials belonging to same class.

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Bipolar magnetic semiconducting behavior in VNbRuAl

Cited by 17 publications

References 40 publications

CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications

CoFeVSb: A Promising Candidate for Spin Valve and Thermoelectric Applications

Topological Spin Semimetal Feature in a Fully Compensated Ferrimagnet CoRuVSi

CoRuVSi: A potential candidate for spin semimetal with promising spintronic and thermoelectric properties

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