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Title: Observation of spin-dependent quantum well resonant tunneling in textured CoFeB layers

We report the observation of spin-dependent quantum well (QW) resonant tunneling in textured CoFeB free layers of single MgO magnetic tunnel junctions (MTJs). The inelastic electron tunneling spectroscopy spectra clearly show the presence of resonant oscillations in the parallel configuration, which are related with the appearance of majority-spin Δ{sub 1} QW states in the CoFeB free layer. To gain a quantitative understanding, we calculated QW state positions in the voltage-thickness plane using the so-called phase accumulation model (PAM) and compared the PAM solutions with the experimental resonant voltages observed for a set of MTJs with different CoFeB free layer thicknesses (t{sub fl} = 1.55, 1.65, 1.95, and 3.0 nm). An overall good agreement between experiment and theory was obtained. An enhancement of the tunnel magnetoresistance with bias is observed in a bias voltage region corresponding to the resonant oscillations.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. IFIMUP and IN-Institute of Nanoscience and Nanotechnology, and Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)
  2. Department of Electronics, AGH University of Science and Technology, 30-059 Krakow (Poland)
  3. INESC-MN and IN-Institute of Nanoscience and Nanotechnology, Rua Alves Redol, 9-1, 1000-029 Lisbon (Portugal)
Publication Date:
OSTI Identifier:
22257813
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 11; Other Information: (c) 2014 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; ELECTRON SPECTROSCOPY; MAGNESIUM OXIDES; MAGNETORESISTANCE; MATHEMATICAL SOLUTIONS; QUANTUM WELLS; SPIN; THICKNESS; TUNNEL EFFECT