Positive local magnetization in the superconducting state of PrOs4Sb12

Local magnetization measurements were performed by micro Hall-probe technique in the superconducting state of PrOs4Sb12, 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 PrOs4Sb12 including the presence of possible spontaneous magnetization is discussed based on the local magnetization measurements.