Stabilization of high Curie temperature in manganite/ruthenate superlattices with ultrathin layers

La_0.7Sr_0.3MnO₃/SrRuO₃ superlattices were grown on SrTiO₃(100) crystals by pulsed-laser deposition. These superlattices exhibited magnetization processes with an intricate interplay between magnetocrystalline anisotropy, magnitude of layer magnetization, spin confinement and antiferromagnetic interlayer coupling. The Curie temperature of the La_0.7Sr_0.3MnO₃ layers so thin as two unit cells was stabilized close to room temperature. Manganite/ruthenate interfaces may be studied as a model system for interfacial reconstruction and charge transfer in a highly correlated ferromagnetic system.