Self-assembling behavior and interface structure in vertically aligned nanocomposite (Pr 0.5 Ba 0.5 MnO 3 ) 1- x :(CeO 2 ) x films on (001) (La,Sr)(Al,Ta)O 3 substrates

Heteroepitaxial oxide-based nanocomposite films possessing a variety of functional properties have attracted tremendous research interest. Here, self-assembled vertically aligned nanocomposite (Pr 0.5 Ba 0.5 MnO 3 ) 1- x :(CeO 2 ) x ( x = 0.2 and 0.5) films have been successfully grown on single-crystalline (001) (La,Sr)(Al,Ta)O 3 substrates by the pulsed laser deposition technique. Self-assembling behavior of the nanocomposite films and atomic-scale interface structure between Pr 0.5 Ba 0.5 MnO 3 matrix and CeO 2 nanopillars have been investigated by advanced electron microscopy techniques. Two different orientation relationships, (001)[100] Pr0.5Ba0.5MnO3 //(001)[1-10] CeO2 and (001)[100] Pr0.5Ba0.5MnO3 //(110)[1-10] CeO2 , form between Pr 0.5 Ba 0.5 MnO 3 and CeO 2 in the (Pr 0.5 Ba 0.5 MnO 3 ) 0.8 :(CeO 2 ) 0.2 film along the film growth direction, which is essentially different from vertically aligned nanocomposite (Pr 0.5 Ba 0.5 MnO 3 ) 0.5 :(CeO 2 ) 0.5 films having only (001)[100] Pr0.5Ba0.5MnO3 //(001)[1-10] CeO2 orientation relationship. Both coherent and semi-coherent Pr 0.5 Ba 0.5 MnO 3 /CeO 2 interface appear in the films. In contrast to semi-coherent interface with regular distribution of interfacial dislocations, interface reconstruction occurs at the coherent Pr 0.5 Ba 0.5 MnO 3 /CeO 2 interface. Our findings indicate that epitaxial strain imposed by the concentration of CeO 2 in the nanocomposite films affects the self-assembling behavior of the vertically aligned nanocomposite (Pr 0.5 Ba 0.5 MnO 3 ) 1-x :(CeO 2 ) x films.