RESISTANCE OF CERAMIC SAMPLES - 2D LOCALIZATION AND TIME-DEPENDENCE

In this payer, we report results of giant magnetoresistance obtained i n a ceramic sample. The results show that between 40 mK and 30 K, the resistance increases as log(T) when temperature decreasing, which coul d be associated with the two-dimensional weak localization effect. The time dependence of the resistance after changing the magnetic field w as also measured at different temperatures. At temperatures higher tha n 2 K, the decay of resistance is associated with the decay of the mag netization. Bellow this temperature, however, the observed large varia tion of the resistance with time after changing the magnetic field may be associated with the reconfiguration of magnetic structure.