Exchange bias and glassy behaviors at high magnetic field in low doped La1-xSrxCoO3

Exchange bias phenomena and the glassy behavior were investigated in low doped La(1-x)Sr(x)CoO(3) cobaltites. Both vertical and horizontal shifts were observed in the hysteresis loops, and the former one vanishes at a critical magnetic field about 40 kOe, the latter one persists to the end. Combining with R - H loop measurement, which shows asymmetric both in resistivity maximum and its corresponding fields, we ascribe the horizontal shifts to the exchange coupling between the surface spin disorder region and ferromagnetic clusters; and the vertical one to the incompletely reversal of ferromagnetic spins. The dc magnetization at low fields and high fields were systematically investigated, and the spin glass region was approved to exist robustly.