[en] The surface morphology of YBa₂Cu₃O_7-δ (YBCO) films is crucial for applications such as multilayering and optical detection. In this article, we showed that the resputtering effect due to the rf plasma can planarize the surface morphology of YBCO films under specific conditions. By setting the relative position and angle of the heater to the gun, the plasma density over the substrate can be altered from an asymmetric to a symmetric distribution. When the substrate was near the plasma, the negative oxygen ions resputtered part of the mobile atoms from the surface of the film back into the plasma, which caused compositional distortion, delaying the merge of grains and leaving uncovered holes. With a longer distance, the resputtering effect was suppressed, and precipitates appeared on the surface of films, resulting in a rougher surface. At an optimum heater-to-gun configuration, the function of the resputtering effect produced a polishing effect on the surface of films, which made a smooth and precipitate-free YBCO film possible. We also found that this film with smooth and precipitate-free morphology exhibited suppressed superconductivity, T_c0 and T_on

[en] La_0.7Ca_0.3MnO₃ thin films grown on SrTiO₃ (100) substrates by off-axis sputtering technique exhibit a fully strained film when the thickness of films is thinner than 25 nm. Transport and magnetic properties of the films for the magnetic field applied parallel to the surface of the films were consistent and could be easily explained by the domain-rotation model. However, these properties were not consistent when the field applied perpendicular to the substrate. The critical field for which peak resistivity was observed in the magnetoresistance measurement, H _c'(-perpendicular ) ∼ 79,500 A m^-1, one order of magnitude higher than the coercive field, H _c perpendicular ∼ 7950 A m^-1. The peak width of the in-plane X-ray diffraction peak (200) of the films as measured by a five-axis X-ray diffractometer showed an exponential decrease to the thickness of films. This broadening cannot be explained by the strain effect alone. We found that nanostructures, such as the ferromagnetic phase segregation in the paramagnetic matrix or the columnar structure in films that introduced excess domain walls, could be responsible for the inconsistency between H _c' perpendicular and H _c perpendicular