The studies of superconductor/ferromagnet (S/F) artificial heterostructures attract much attention. Using such structures it is possible to probe in detail the interplay between superconductivity and ferromagnetism. Recent theoretical model  predicts the existence of an indirect exchange coupling between ferromagnetic layers across the superconducting layers, similar to the coupling observed in giant magnetoresistance (GMR) systems.
The theory suggests that the most relevant heterostructures to observe such effect are structures built of layers of manganites with colossal magnetoresistance (CMR) and the high temperature superconductors (HTSC). In this talk we describe the experimental studies [2,3] of the structure, transport and magnetic properties of CMR/HTSC heterostructures, based on manganites La0.67Sr0.33MnO3 (LSMO) and superconductor YBa2Cu2O7 (YBCO). Experimental results support the existence of indirect exchange coupling. The interesting effects of interplay of superconductivity and magnetism in LSMO/YBCO will be presented.
 C.A.R. Sa de Melo Physica C 387, 17(2003).
 P. Przyslupski et al., J. Appl. Phys. 95,2906(2004).
 P. Przyslupski et al., Phys. Rev. B 69,134428(2004).