title: Evidence of superparamagnetic co clusters in pulsed laser deposition-grown Zn0.9Co0.1O thin films using atom probe tomography.
abstract: Nanosized Co clusters (of about 3 nm size) were unambiguously identified in Co-doped ZnO thin films by atom probe tomography. These clusters are directly correlated to the superparamagnetic relaxation observed by ZFC/FC magnetization measurements. These analyses provide strong evidence that the room-temperature ferromagnetism observed in the magnetization curves cannot be attributed to the observed Co clusters. Because there is no experimental evidence of the presence of other secondary phases, our results reinforce the assumption of a defect-induced ferromagnetism in Co-doped ZnO diluted magnetic semiconductors.
authors.affiliation: Groupe de Physique des Matériaux, UMR 6634 CNRS, Université et INSA de Rouen , Avenue de l'Université, B.P. 12, 76801 Saint Etienne du Rouvray, France. rodrigue.larde@univ-rouen.fr
authors.forename: Rodrigue
authors.initials: R
authors.lastname: Lardé
authors.forename: Etienne
authors.initials: E
authors.lastname: Talbot
authors.forename: Philippe
authors.initials: P
authors.lastname: Pareige
authors.forename: Herrade
authors.initials: H
authors.lastname: Bieber
authors.forename: Guy
authors.initials: G
authors.lastname: Schmerber
authors.forename: Silviu
authors.initials: S
authors.lastname: Colis
authors.forename: Véronique
authors.initials: V
authors.lastname: Pierron-Bohnes
authors.forename: Aziz
authors.initials: A
authors.lastname: Dinia