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Title: Controlling magnetic domain wall motion in the creep regime in He{sup +}-irradiated CoFeB/MgO films with perpendicular anisotropy

This study presents the effective tuning of perpendicular magnetic anisotropy in CoFeB/MgO thin films by He{sup +} ion irradiation and its effect on domain wall motion in a low field regime. Magnetic anisotropy and saturation magnetisation are found to decrease as a function of the irradiation dose which can be related to the observed irradiation-induced changes in stoichiometry at the CoFeB/MgO interface. These changes in the magnetic intrinsic properties of the film are reflected in the domain wall dynamics at low magnetic fields (H) where irradiation is found to induce a significant decrease in domain wall velocity (v). For all irradiation doses, domain wall velocities at low fields are well described by a creep law, where Ln(v) vs. H{sup −1∕4} behaves linearly, up to a maximum field H*, which has been considered as an approximation to the value of the depinning field H{sub dep}. In turn, H* ≈ H{sub dep} is seen to increase as a function of the irradiation dose, indicating an irradiation-induced extension of the creep regime of domain wall motion.
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Institut d'Electronique Fondamentale, Université Paris-Sud, UMR CNRS 8622, 91405 Orsay (France)
  2. Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, 20864 Agrate (MB) (Italy)
  3. Singulus Technology AG, Hanauer Landstrasse 103, 63796 Kahl am Main (Germany)
Publication Date:
OSTI Identifier:
22486341
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; APPROXIMATIONS; CREEP; HELIUM IONS; INTERFACES; IRRADIATION; MAGNESIUM OXIDES; MAGNETIC FIELDS; MAGNETIZATION; RADIATION DOSES; SATURATION; STOICHIOMETRY; THIN FILMS; TUNING; WALLS