Fabrication and characterization of heteroepitaxial bilayers of La–Ca–Mn–O/Y–Ba–Cu–O

We have fabricated La0.67Ca0.33MnO3/YBa2Cu3Oy heteroepitaxial bilayers on SrTiO3 (1 0 0) substrates by rf magnetron sputtering. The La0.67Ca0.33MnO3/YBa2Cu3Oy bilayers were characterized by X-ray diffraction, rocking curve measurements, scanning electron microscope and dc four-probe measurements. Both La0.67Ca0.33MnO3 and YBa2Cu3Oy layers show excellent crystallinity indicated by their sharp and narrow rocking curves. The La0.67Ca0.33MnO3/YBa2Cu3Oy bilayers exhibit a very smooth surface. The relation between the superconducting critical current density of YBa2Cu3Oy and temperature was also investigated.