Series of bulk magnetic-phase transitions in NaxCoO2NaxCoO2: A μSRμSR study

Using muon spin rotation, well-defined bulk ∼100%∼100% magnetic phases in NaxCoO2NaxCoO2 are revealed. A novel magnetic phase is detected for x=0.85x=0.85 with the highest transition temperature ever observed for x⩾0.75x⩾0.75. This stresses the diversity of x⩾0.75x⩾0.75 magnetic phases and the link between magnetic and structural degrees of freedom. For x=1.0x=1.0, no magnetism is detected as expected for the low spin state of Co3+Co3+. For the charge-ordered x=0.50x=0.50 compound, a cascade of transitions is observed below 85 K.