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Title: Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ; ;  [3] ; ; ;  [4] ;  [3] ;  [5]
  1. Department of Engineering Sciences, Uppsala University, 75121 Uppsala (Sweden)
  2. Department of Physics, University of Colorado, Colorado Springs, Colorado 80918 (United States)
  3. Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden)
  4. Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden)
  5. (Sweden)
Publication Date:
OSTI Identifier:
22415195
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COPPER; COUPLING CONSTANTS; FERROMAGNETIC RESONANCE; HYSTERESIS; IRON; LAYERS; NICKEL; SILICA; SILICON OXIDES; SIMULATION; STRONG-COUPLING MODEL; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY