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Combinatorial optimization for high spin polarization in Heusler alloy composition-spread thin films by anisotropic magnetoresistance effect.
- Source :
- APL Materials; Oct2023, Vol. 11 Issue 10, p1-12, 12p
- Publication Year :
- 2023
-
Abstract
- Half-metallic Heusler alloys are promising candidates for spintronic applications due to their high spin polarization. However, the spin polarization strongly depends on the atomic composition, which is time-consuming to optimize from various compositional combinations. Here, we demonstrate a high-throughput compositional optimization method for high spin polarization in Co<subscript>2</subscript>(Mn, Fe)Ge Heusler alloys by combining composition-spread films and anisotropic magnetoresistance (AMR) measurement. Two types of composition-spread films of polycrystalline Co<subscript>2</subscript>(Mn<subscript>1−x</subscript>Fe<subscript>x</subscript>)Ge and (Co<subscript>2</subscript>Mn<subscript>0.5</subscript>Fe<subscript>0.5</subscript>)<subscript>1−y</subscript>Ge<subscript>y</subscript> are fabricated on SiO<subscript>2</subscript>/Si substrates by combinatorial sputtering deposition, followed by post-annealing. The compositional dependence of AMR shows the largest negative AMR ratio of −0.13% and the smallest temperature dependence of the resistance change of AMR for y = 0.25 in the (Co<subscript>2</subscript>Mn<subscript>0.5</subscript>Fe<subscript>0.5</subscript>)<subscript>1−y</subscript>Ge<subscript>y</subscript> composition-spread film, suggesting the highest spin polarization and the closest nature to the ideal half-metal at this composition ratio. To verify this, we also develop a new technique to measure the compositional dependence of spin polarization by measuring the spin accumulation signals of nonlocal spin-valve devices fabricated on the composition-spread films and observe the highest spin polarization of 82% for y = 0.24. This confirms a clear qualitative correlation between the large negative AMR ratio and high spin polarization. Our combinatorial method using the composition-spread films and the AMR measurement proves to be a facile way for optimizing the fabrication conditions of half-metallic Heusler alloys with high spin polarization. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 2166532X
- Volume :
- 11
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- APL Materials
- Publication Type :
- Academic Journal
- Accession number :
- 173336206
- Full Text :
- https://doi.org/10.1063/5.0169124