AFM images of Ir nanoparticles grown on (100) by using different deposition condition. (a) , , , (b) , , .
(a) Cross-section TEM bright field image of a 100-nm-thick YBCO film deposited on Ir nanoparticle-decorated substrate. Arrows show the location of the Ir-rich particles at the interface. (b) SAED pattern, taken along the  zone axis, reveals presence of planar defects (streaks) and the formation of a secondary phase in the vicinity of the Ir particle.
Magneto-optical images of flux penetration at 5 K into 100-nm-thick YBCO films grown on (a) untreated , and (b) decorated with Ir nanoparticles [same sample presented in Fig. 1(a)]. Images are across the full width of the samples (3 mm). Dark central area is the region where the magnetic field is excluded .
Temperature dependence of magneto-optically determined values for the two samples presented in Figs. 2(a) and 2(b).
Comparison of the field-dependent transport critical current densities at 77 K for three sets of 200-nm-thick YBCO films grown on STO substrates with and without Ir nanoparticles. The open symbols are for control and solid symbols are for nanoparticles∕STO. Inset shows the characteristics of similar samples films with optimized YBCO deposition conditions. Curves through the data points follow from the model Eq. (1).
The pinning force density for the same samples as presented in the inset of Fig. 5, as a function of magnetic field at 77 K. Lines are fits to model relation, Eq. (1).
Angular dependence of (77 K) at 0.5 and 1 T for the two YBCO films (set 3; with and without nanoparticles) presented in the Fig. 5 inset.
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