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Title: Over 50% reduction in the formation energy of Co-based Heusler alloy films by two-dimensional crystallisation

Crystalline formation of high magnetic-moment thin films through low-temperature annealing processes compatible with current semiconductor technologies is crucial for the development of next generation devices, which can utilise the spin degree of freedom. Utilising in-situ aberration corrected electron microscopy, we report a 235 °C crystallisation process for a Co-based ternary Heusler-alloy film whose initial nucleation is initiated by as few as 27 unit cells. The crystallisation occurs preferentially in the 〈111〉 crystalline directions via a two-dimensional (2D) layer-by-layer growth mode; resulting in grains with [110] surface normal and [111] plane facets. This growth process was found to reduce the crystallisation energy by more than 50% when compared to bulk samples whilst still leading to the growth of highly ordered grains expected to give a high degree of spin-polarisation. Our findings suggest that the 2D layer-by-layer growth minimises the crystallisation energy allowing for the possible implementation of highly spin-polarised alloy films into current chip and memory technologies.
Authors:
; ; ; ;  [1] ;  [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
  2. (United Kingdom)
  3. Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom)
  4. (Japan)
Publication Date:
OSTI Identifier:
22311145
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; COBALT COMPOUNDS; CRYSTAL GROWTH; CRYSTALLIZATION; CURRENTS; DEGREES OF FREEDOM; ELECTRON MICROSCOPY; FORMATION HEAT; HEUSLER ALLOYS; LAYERS; MAGNETIC MOMENTS; POLARIZATION; SEMICONDUCTOR MATERIALS; SPIN; SURFACES; THIN FILMS; TWO-DIMENSIONAL CALCULATIONS