  Complex oxides exhibit a variety of unusual physical properties, which can be
used for designing novel electronic devices. Here we fabricate and study
experimentally nano-scale Superconductor/ Ferromagnet/Superconductor junctions
with the high-Tc cuprate superconductor YBa2Cu3O7 and the colossal
magnetoresistive (CMR) manganite ferromagnets LaXMnO3 (X: Ca or Sr). We
demonstrate that in a broad temperature range the magnetization of a manganite
nanoparticle, forming the junction interface, switches abruptly in a
mono-domain manner. The CMR phenomenon translates the magnetization loop into a
hysteretic magnetoresistance loop. The latter facilitates a memory
functionality of such a junction with just a single CMR ferromagnetic layer.
The orientation of the magnetization (stored information) can be read out by
simply measuring the junction resistance in an applied magnetic field. The CMR
facilitates a large read-out signal in a small applied field. We argue that
such a simple single layer CMR junction can operate as a memory cell both in
the superconducting state at cryogenic temperatures and in the normal state up
to room temperature.
