Growth, characterization and studies on thin films of high Tc cuprates and colossal magnetoresistive manganites, and their heterostructures

The interplay between superconductivity (SC) and ferromagnetic (FM) orderings have been investigated using multilayer-structures comprising of alternately stacked high temperature superconductor YBa2Cu3O6+x (YBCO) and colossal magnetoresistive manganite La1-xPbxMnO3 (LPMO). The YBCO/LPMO heterostructures have been in-situ fabricated using pulsed laser deposition technique. The magneto-transport and magnetic studies revealed, for the first time, that LPMO layers get antiferromagnetically coupled through intermittent YBCO layer. The YBCO/LPMO structures were also employed for fabrication of three-terminal spin-injection devices, which showed a gain of ∼2. In addition, several studies on YBCO and LPMO thin films were conducted. Some of these are (i) influence of grain boundaries on thermodynamic-induced fluctuation conductivity in YBCO film, (ii) in-plane and out-of-plane anisotropic magnetoresistance in LPMO films, (iii) investigation of high magnetoresistance in nanocrystalline LPMO films and (iv) ferromagnetic resonance studies in single and nanocrystalline LPMO films. (author)