Series Of Bulk Magnetic-Phase Transitions In Naxcoo2: A Mu Sr Study

Using muon spin rotation, well-defined bulk similar to 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 >= 0.75. This stresses the diversity of x >= 0.75 magnetic phases and the link between magnetic and structural degrees of freedom. For x = 1.0, no magnetism is detected as expected for the low spin state of Co3+. For the charge-ordered x = 0.50 compound, a cascade of transitions is observed below 85 K. (c) 2005 Elsevier B.V. All rights reserved.