Nanostructure of Giant Magnetoresistance Heterogeneous Alloys Ni0.20Ag0.80 After Annealing

C. Revenant-Brizard; J.R. Regnard; J. Mimault; O. Proux; B. Dieny; B. Mevel

doi:doi:10.1051/jp4:19972150

Numéro		J. Phys. IV France Volume 7, Numéro C2, Avril 1997 Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure


Page(s)		C2-1111 - C2-1113
DOI		https://doi.org/10.1051/jp4:19972150

Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure

J. Phys. IV France 7 (1997) C2-1111-C2-1113
DOI: 10.1051/jp4:19972150

Nanostructure of Giant Magnetoresistance Heterogeneous Alloys Ni_0.20Ag_0.80 After Annealing

C. Revenant-Brizard¹, J.R. Regnard^{1, 2}, J. Mimault³, O. Proux³, B. Dieny¹ and B. Mevel¹

¹ Département de Recherche Fondamentale sur la Matière Condensée SP2M, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble cedex 9, France
² Université Joseph Fourier, BP. 53 X, 38041 Grenoble cedex, France
³ Laboratoire de Métallurgie Physique, SP2MI, Bd. 3, Téléport 2, BP. 179, 86960 Futuroscope cedex, France

Abstract
Heterogeneous alloys Ni_0.20Ag_0.80, presenting giant magnetoresistance properties, have been studied by Total Electron Yield X-ray absorption spectroscopy at liquid nitrogen temperature at the Ni K edge from as-deposited to annealed stages. Up to 150°C annealing, the Ni atoms are mainly in small poorly ordered agglomerates and the local Ni atomic environment is very stable and disordered. Up to 250°C annealing, some Ni atoms occupy substitutional sites in the Ag matrix and 40 to 50 % of the Ni nearest neighbors are Ag atoms. After annealing at 400°C during 10 mn, the nanostructures evolve towards larger, more compact and well ordered granules. The Ni-Ni distance varies from 0.246 to 0.248 nm as the annealing temperature increases indicating that the small agglomerates are under strain in the Ag matrix.