title: Cascade of bulk magnetic phase transitions in NaxCoO2 as studied by muon spin rotation.
abstract: Using muon spin rotation, well-defined bulk approximately 100% magnetic phases in NaxCoO2 are revealed. A novel magnetic phase is detected for x=0.85 with the highest transition temperature ever observed for x>or=0.75. This stresses the diversity of x>or=0.75 magnetic phases and the link between magnetic and structural degrees of freedom. For the charge-ordered x=0.50 compound, a cascade of transitions is observed below 85 K. From a detailed analysis of our data, we conclude that the ordered moment varies continuously with temperature and suggest that the two secondary transitions at 48 and 29 K correspond to a moderate reorientation of antiferromagnetically coupled moments.
authors.affiliation: Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, 91405 Orsay, France.
authors.forename: P
authors.initials: P
authors.lastname: Mendels
authors.forename: D
authors.initials: D
authors.lastname: Bono
authors.forename: J
authors.initials: J
authors.lastname: Bobroff
authors.forename: G
authors.initials: G
authors.lastname: Collin
authors.forename: D
authors.initials: D
authors.lastname: Colson
authors.forename: N
authors.initials: N
authors.lastname: Blanchard
authors.forename: H
authors.initials: H
authors.lastname: Alloul
authors.forename: I
authors.initials: I
authors.lastname: Mukhamedshin
authors.forename: F
authors.initials: F
authors.lastname: Bert
authors.forename: A
authors.initials: A
authors.lastname: Amato
authors.forename: A D
authors.initials: AD
authors.lastname: Hillier