Discussion again of the interfacial tunneling in granular perovskite La0.82Sr0.18MnO3

The spin-dependent intergranular tunneling in granular perovskites Lao(0.82 )Sr(0.18)MnO(3) has been investigated. A series of experimental evidences, including magnetization, heat capacity, structure distortions and magnetore sistance, have been given to demonstrate that the intergranular tunneling s tems from a spin-dependent surface effect, which is related to the magnetic difference between the core and the surface of the perovskite grain, and t he related tunnel-type magnetoresistance results from a field-induced chang e of interfacial magnetic configuration. (C) 1999 Elsevier Science B.V.