Sputter-engineering a first-order magnetic phase transition in sub-15-nm-thick single-crystal FeRh films
| Autor: | Trevor P. Almeida, Damien McGrouther, Stephen McVitie, L. Benito, Laura Clark, Christopher H. Marrows, T. A. Moore |
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| Rok vydání: | 2020 |
| Předmět: |
Diffraction
Phase transition Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Spintronics Alloy 02 engineering and technology Surface finish engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Sputtering 0103 physical sciences engineering General Materials Science Specular reflection 010306 general physics 0210 nano-technology Single crystal |
| Zdroj: | Physical Review Materials. 4 |
| ISSN: | 2475-9953 |
| Popis: | Equiatomic FeRh alloys undergo a fascinating first-order metamagnetic phase transition (FOMPT) just above room temperature, which has attracted reinvigorated interest for applications in spintronics. Until now, all attempts to grow nanothin FeRh alloy films have consistently shown that FeRh layers tend to grow in the Volmer-Weber growth mode. Here we show that sputter-grown sub-15-nm-thick FeRh alloy films deposited at low sputter-gas pressure, typically ∼0.1 Pa, onto (001)-oriented MgO substrates, grow in a peening-induced Frank-van der Merwe growth mode for FeRh film thicknesses above 5 nm, circumventing this major drawback. The bombardment of high-energy sputtered atoms, the atom-peening effect, induces a rebalancing between adsorbate-surface and adsorbate-adsorbate interactions, leading to the formation of a smooth continuous nanothin FeRh film. Chemical order in the films increases with the FeRh thickness, tFeRh, and varies monotonically from 0.75 up to 0.9. Specular x-ray diffraction scans around Bragg peaks show Pendellösung fringes for films with tFeRh≥5.2 nm, which reflects in smooth well-ordered densified single-crystal FeRh layers. The nanothin film's roughness varies from 0.6 down to about 0.1 nm as tFeRh increases, and scales linearly with the integral breadth of the rocking curve, proving its microstructured origin. Magnetometry shows that the FOMPT in the nanothin films is qualitatively similar to that of the bulk alloy, except for the thinnest film of 3.7 nm. |
| Databáze: | OpenAIRE |
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