Local Orientation Variations in YBCO Films on Technical Substrates - A Combined SEM and EBSD Study

Abstract

Scanning electron microscope imaging and electron backscatter diffraction are applied to 400 nm thick YBCO films grown on Ni-9at.%W and ABAD-YSZ tape. On Ni-9at.%W tape, the orientation of YBCO strongly varies from grain to grain, which is attributed to the different orientations of the underlying substrate grains with regard to the surface normal. On ABAD-YSZ, the structures causing the orientation variations are observed on a micrometer scale only, which is attributed to the granularity of the template. In contrast to Ni-9at.%W where no preferred misorientation axis is notable within single substrate grains, the misorientation of YBCO on the ABAD-YSZ tape is primarily caused by lattice rotations about the sample normal.

Effect of Silver Doping on the Superconducting and Structural Properties of YBCO Films Grown by PLD on Different Templates

“…At the same time, scanning Hall probe microscopy (SHPM) provided additional information on the local distribution of the critical current density. Similar studies have been performed previously on pure YBCO layers grown on metallic templates [ 23 , 24 , 25 ].…”

“…Figure 1 c,d,g,h clearly show a granular surface structure of the films with quite sharp grain boundaries (GBs). Moreover, the porosity of the films varied from grain to grain as a consequence of the individual out-of-plane orientation of the original grain of the metal template [ 23 ]. Some grains showed variation in the porosity on one and the same Ni grain, where these features were aligned along the rolling direction (compare Figure 1 d).…”

“…Although both templates have a granular structure, the shape, size, and morphology of the grains are fundamentally different. In particular, the films on the IBAD-MgO-based templates are more uniform and, therefore, the granularity of the films was observed only on the micrometer scale [ 23 ]. In order to obtain the relevant information on the misorientation distribution, we used a step size of 20 nm for the EBSD map.…”

Tailoring Microstructure and Superconducting Properties in Thick BaHfO3 and Ba2 Y(Nb/Ta)O6 Doped YBCO Films on Technical Templates

“…Doped YBCO films on buffered Ni-W tapes show a similar microstructure to that of films on ABAD-YSZ tapes with the exception of the additional global grain network arising from the template (∼20 to 50 μm diameter grains on Ni-W, <1 μm on ABAD-YSZ [42]). Strong (00 ) peaks in XRD measurements (data not shown) indicate a highly c-axis oriented growth; additional peaks of the dopant material appear for the 5 mol% BHO (2.2 vol%) and BYNTO doped samples.…”

“…A minor BHO component of c-axis oriented columns with a fan-shaped structure is also present in these samples. In addition to the deposition parameters, the microstructure might depend on the vicinal angle of the underlying substrate [42], [43]. As the grains on RABiTS Ni-W exhibit an individual tilt of the Ni-W [001] direction towards the tape normal, an additional grain to grain variance of the microstructure cannot be excluded.…”