title: Nanostructure and giant magnetoresistive properties of granular systems.
abstract: This article aims to make a connection between the microstructures of various nanostructured alloys and giant magnetoresistive (GMR) properties. The GMR behavior of nanoclusters embedded in a nonmagnetic matrix differs considerably from an alloy with the content of a magnetic phase above the percolation threshold; that is to say, an increase of GMR effect upon going from 300 to 10 K for the former and a decrease of the GMR effect for the latter. The following materials systems were examined with high-resolution transmission electron microscopy and magnetoelectrical resistance measurements: magnetic Co and CoFe nanoclusters in a Au matrix, NiFe clusters in a Cu matrix, and NiFe/Cu spinodal decomposition waves with interconnection of the magnetic phase. After annealing (> or = 300 degrees C), Co particles in Au become semi- or incoherent, whereas under other conditions and in all other systems, the interfaces remain coherent. This state of coherency at the interface between magnetic particles and a nonmagnetic matrix turned out to have a detectable influence on the GMR behavior.
authors.affiliation: Department of Applied Physics, Materials Science Center, The Netherlands Institute for Metals Research, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kooi
authors.forename: T
authors.initials: T
authors.lastname: Vystavel
authors.forename: J T
authors.initials: JT
authors.lastname: De Hosson
mesh_terms: D003300:Copper / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D017097:Electric Impedance; D004574:Electromagnetic Fields; D006047:Gold Alloys / Q000737:chemistry*; D008280:Magnetics; D008422:Materials Testing / Q000379:methods; D008854:Microscopy, Electron; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D009532:Nickel / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013499:Surface Properties
chemical_list: D006047:Gold Alloys; C062136:nickel copper alloy; D003300:Copper; D009532:Nickel