Series of Bulk Magnetic Phase Transitions in NaxCoO2: a muSR study
/ Authors
P. Mendels, D. Bono, J. Bobroff, G. Collin, D. Colson, N. Blanchard, H. Alloul, I. Mukhamedshin, F. Bert, A. Amato
and 1 more author
/ Abstract
Using muon spin rotation, well-defined bulk ∼ 100% magnetic phases in Na x CoO 2 are revealed. A novel magnetic phase is detected for x = 0 . 85 with the highest transition temperature ever observed for x ≥ 0 . 75. This stresses the diversity of x ≥ 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 K and 29 K correspond to a moderate reorientation of antiferromagnetically coupled moments. Hexagonal parameters