Abstract
We present initial investigation of the superconductor-ferromagnet-superconductor (SFS) heterostructures of nanometer dimensions prepared by the gallium focused ion beam (FIB) technology. The SFS heterostructures were realized on the basis of high-Tc superconducting YBa2Cu3Ox and ferromagnetic La0.67Sr0.33MnO3 thin films. SFS weak link junctions require dimensions of the weak link connection in the range of nanometer size realizable by FIB patterning. On the other side the gallium focused ion beam might bring about unacceptable degradation of the superconducting as well as ferromagnetic thin film properties. The presented results show that FIB offers a suitable procedure for realization of nanometer size devices but some degradation of the ferromagnetic and superconducting properties was observed. Solution of this problem will be achieved in the next stage of our investigations.