Sputter-engineering a first-order magnetic phase transition in sub-15-nm-thick single-crystal FeRh films

Benito, L., Clark, L. , Almeida, T.P. , Moore, T.A., , and , (2020) Sputter-engineering a first-order magnetic phase transition in sub-15-nm-thick single-crystal FeRh films. Physical Review Materials, 4(12), 123402. (doi: 10.1103/PhysRevMaterials.4.123402)

Abstract

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 re-balancing 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, t FeRh , and varies monotonically from 0.75 up to 0.9. Specular x-ray diffraction scans around Bragg peaks show Pendell"{o}sung fringes for films with t FeRh ≥ 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 t FeRh increases, and scales linearly with the integral breadth of the rocking curve, proving its microstructured origin.

• Item Type: Articles
• Additional Information: The authors acknowledge funding support from the European Commission through a Marie Sk lodowska-Curie Intra-European Fellowship (MSCA-IF-2016, Contract No. 748691) and the Engineering and Physical Sciences Research Council in the UK (Grants No. EP/M018504/1 and EP/M019020/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McGrouther, Dr Damien and Clark, Dr Laura and McVitie, Professor Stephen and Almeida, Dr Trevor
• Authors: Benito, L., Clark, L., Almeida, T.P., Moore, T.A., , , and ,
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review Materials
• Publisher: American Physical Society
• ISSN: 2475-9953
• ISSN (Online): 2475-9953
• Published Online: 03 December 2020
• Copyright Holders: Copyright © 2020 American Physical Society
• First Published: First published in 4(12):123402
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
171224		Current-driven domain wall motion and magnetomemristance in FeRh-based nanostructures	Stephen McVitie	Engineering and Physical Sciences Research Council (EPSRC)	EP/M019020/1	P&S - Physics & Astronomy