Surface Roughness and Grain Size Characterization of Annealing Temperature Effect For Growth Gallium and Tantalum Doped Ba0.5 Sr0.5TiO3Thin Film - Irzaman, Irzaman; Department of Physics, FMIPA Bogor Agricultural Unversity (BAU), BAU Campus Darmaga Gedung Wing S Bogor, Indonesia – 16680 (PPIKSN-BATAN, 2011)