Positive local magnetization in the superconducting state of PrOs4Sb12

Local magnetization measurements were performed by micro Hall-probe technique in the superconducting state of PrOs 4 Sb 12 , in which the time-reversal symmetry is broken. We have observed positive, i.e. ferromagnetic like, local magnetic induction just below the superconducting transition temperature, which changes into a usual Meissner signal as temperature goes down. The signal is dependent on the measuring points of the sample surface, and may be interpreted as a sign of the dilute magnetic moment arising from spontaneous current in the superconducting state. The characteristics of the superconductivity in PrOs 4 Sb 12 including the presence of possible spontaneous magnetization is discussed based on the local magnetization measurements.