Magnetoresistive effects in ferromagnet-superconductor multilayers - art. no. 10J108

摘要

We consider a nanoscale system consisting of manganite-ferromagnet and cuprate-superconductor multilayers in a spin-valve configuration. The magnetization of the bottom manganite ferromagnet is pinned by a manganite antiferromagnet. The magnetization of the top manganite ferromagnet is coupled to the bottom one via indirect exchange through the superconducting layers. We study the behavior of the critical temperature and the magnetoresistance as a function of an externally applied parallel magnetic field, when the number of cuprate-superconductor layers are changed. There are two typical behaviors in the case of a few monolayers of the cuprates: (a) for small magnetic fields, the critical temperature and the magnetoresistance change abruptly when the flipping field of the top manganite ferromagnet is reached, and (b) for large magnetic fields, the multilayered system reenters the zero-resistance (superconducting) state after having become resistive (normal). (c) 2005 American Institute of Physics.