Ferromagnetic-semiconductor-singlet-(or triplet) superconductor-ferromagnetic-semiconductor systems as possible logic circuits and switches

We consider thin superconducting (S) films of thickness d much less than xi (0), sandwiched between two ferromagnetic semiconducting insulators (FI) w ith differently orientated magnetizations-the FI-S-FI system. We calculate the dependence of the superconducting critical temperature on the orientati on of the magnetization in the insulators and on the thickness of the super conducting film. The calculations are done for singlet as well as triplet s uperconductors. In the singlet case T-c depends on the relative orientation of the left and right magnetization only, while in the triplet case T-c de pends on the absolute orientation of magnetization. The latter property can serve as a kind of spin spectroscopy of triplet and unconventional superco nductors, for instance in resolving the structure of the triplet order para meter in the recently discovered layered superconductor Sr2RuO4. The possib ility of logic circuits and switches, which are based on the FI-S-FI system s with arbitrary orientation of magnetizations in FT films, is analyzed too .