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Title: Sign of the spin-polarization in cobalt-iron nitride films determined by the anisotropic magnetoresistance effect

We present the anisotropic magnetoresistance (AMR) properties in Fe{sub 4}N, Co{sub 3}FeN and Co{sub 4}N epitaxial thin films grown on SrTiO{sub 3}(001) substrates using molecular beam epitaxy. A negative AMR effect was observed in the Fe{sub 4}N and Co{sub 3}FeN films below 300 K. This behavior was attributed to the negative spin-polarizations of both the electrical conductivity and density of states at the Fermi level. The sign of the AMR ratio changed at ∼140 K in the Co{sub 4}N film and was negative below 140 K. Diffraction lines corresponding to the (100) plane were clearly observed in the ϕ-2θ{sub χ} (in-plane) x-ray diffraction patterns for the Fe{sub 4}N and Co{sub 3}FeN films but not for the Co{sub 4}N film. This indicated that nitrogen atoms were present at the body center of each unit cell in the Fe{sub 4}N and Co{sub 3}FeN films, whereas they were lacking in the Co{sub 4}N film. This assumption is discussed with energetic calculations using a spin density-functional theory.
Authors:
 [1] ;  [2] ;  [2] ; ;  [3] ; ; ;  [4] ;  [4] ;  [5]
  1. Japan Society for the Promotion of Science (JSPS), 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan)
  2. (Japan)
  3. Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, 6-6-05 Aobayama, Sendai 980-8579 (Japan)
  4. Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)
  5. (AIST), AIST Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)
Publication Date:
OSTI Identifier:
22314558
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; 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; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; ATOMS; COBALT; DENSITY FUNCTIONAL METHOD; FERMI LEVEL; IRON; IRON NITRIDES; MAGNETORESISTANCE; MOLECULAR BEAM EPITAXY; NITROGEN; SPIN; SPIN ORIENTATION; STRONTIUM TITANATES; SUBSTRATES; THIN FILMS; X-RAY DIFFRACTION