Metamagnetic transition in Na0.85CoO2 single crystals -: art. no. 187203

We report the magnetization, specific heat, and transport measurements of a high quality Na0.85CoO2 single crystal in applied magnetic fields up to 14 T. At high temperatures, the system is in a paramagnetic phase. It undergoes a magnetic phase transition below similar to20 K. For the field H parallel to c, the measurement data of magnetization, specific heat, and magnetoresistance reveal a metamagnetic transition from an antiferromagnetic state to a quasiferromagnetic state at about 8 T at low temperatures. However, no transition is observed in the magnetization measurements up to 14 T for H perpendicular to c. The low temperature magnetic phase diagram of Na0.85CoO2 is determined.