| 1. |
- Barwal, Vineet, et al.
(författare)
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Spin gapless semiconducting behavior in inverse Heusler Mn2-xCo1 +/- xAl (0 x 1.75) thin films
- 2021
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 518
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Tidskriftsartikel (refereegranskat)abstract
- We correlate the structural, electrical, and magnetotransport properties of co-sputtered Mn2-xCo1?xAl full Heusler alloy thin films (0 x 1.75) in terms of Co/Mn concentration variation concerning the spin gapless semiconducting (SGS) behavior. The alloy thin films are found to stabilize in B2 order for near stoichiometric films, i.e. (x = 0 and x = 1), with the gradual change in the ordering and lattice parameter through Mn concentration variation. Magnetization measurements in Mn2-xCo1?xAl thin films reveal the ferromagnetic and ferrimagnetic character for x = 1.75, 1.5, 1.25 & 1, and x = 0, 0.5 & 0.75, respectively. The longitudinal resistivity measurement revealed that the films exhibit semiconducting behavior with a change in sign of the temperature coefficient of resistance with temperature. The anomalous Hall conductivity values for the Mn2-xCo1?xAl thin films are extracted from the Anomalous Hall effect (AHE) measurements. The non-saturating positive MR (linear in H) is being reported for the first time in the Mn2CoAl thin films. The value of the AHE coefficient and positive MR together serve as a piece of experimental evidence for the SGS character in the thin film. The SGS behavior becomes predominant at higher Mn concentration. Highly resistive thin films with ferromagnetic (ferrimagnetic) character in Co2MnAl (Mn2CoAl) could be beneficial for semiconductor spintronics, where we need a good resistive element to match up with Silicon base substrate.
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| 2. |
- Hait, S., et al.
(författare)
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Impact of ferromagnetic layer thickness on the spin pumping in Co60Fe20B20/Ta bilayer thin films
- 2021
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Ingår i: Journal of Materials Science-Materials in Electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 32, s. 12453-12465
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Tidskriftsartikel (refereegranskat)abstract
- We report the tuneable spin angular momentum transfer (spin pumping) from Co60Fe20B20 (CFB) amorphous alloy into the Ta heavy metal nanolayers. All the films are grown on Si (100) substrate at room temperature using ion-beam sputtering technique. Structural studies reveal that the grown Ta films over amorphous CFB are crystalline even at ultrathin regime. The bilayers possess very low interface roughness (< 0.5 nm) and are continuous throughout the thickness range. Comparative analysis of the spin pumping in CFB (4, 6 and 8 nm) as a function of the Ta thickness (vary from 1 to 10 nm in step of 1 nm) has been performed employing ferromagnetic resonance (FMR) spectroscopy. It is observed that the effective damping increase exponentially with the increase of Ta, (i.e. follows ballistic spin transport) in two series of CFB (4 nm)/Ta (0-10 nm) and CFB(6 nm)/Ta (0-10 nm) bilayers, which is characteristic of normal spin pumping. However, the anomalous behaviour has been observed for CFB (8 nm)/Ta (0-10 nm) bilayer series where the spin current generated in Ta with the thicker CFB behaves oppositely. The results demonstrate the strong dependence of ferromagnet thickness on the spin pumping into the Ta nanolayers. This study paves the way to choose suitable ferromagnetic layer thickness for spin current-induced switching applications in spintronics.
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| 3. |
- Husain, Sajid, et al.
(författare)
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Probing Charge Density Wave Effects in 1T-TaS2 Monolayer/Ni81Fe19 Heterostructure: A Spin Dynamics Approach
- 2021
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Ingår i: Acs Applied Electronic Materials. - : American Chemical Society (ACS). - 2637-6113. ; 3:8, s. 3321-3328
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Tidskriftsartikel (refereegranskat)abstract
- The transition metal dichalcogenide 1T-TaS2 is known to exhibit a number of collective electronic states known as charge density wave (CDW) instabilities. Intriguing phenomena such as a large damping-like spin-orbit torque (SOT) have been reported in monolayer 1T-TaS2 [Nano Lett. 2020, 20 (9), 6372-6380]. Probing of CDWs in monolayer thick 1T-TaS2 has been an inconceivable task. Here, the temperature-dependent spin dynamics and the effect of CDWs in the 1T-TaS2(monolayer)/Ni81Fe19 (Py) (7 nm) heterostructure are reported. Employing ferromagnetic resonance, the effect of the different commensurate (C) and nearly commensurate (NC) CDW states on the spin dynamics during heating and cooling cycles has been characterized by use of the effective damping constant and the spin mixing conductance of the heterostructure. In addition, these CCDW and NCCDW states, which affect the SOT efficiencies due to damping- and field-like SOTs, have been evaluated by using angle-dependent planar Hall effect measurements in controlled cooling and heating cycles. Our findings provide a fundamental understanding of the effect of different CDW states on the spin dynamics in twodimensional 1T-TaS2 monolayer interfaced Py.
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