BaZrO 3 nanorods are known to be effective pinning centers as c-axis-correlated pinning centers. Furthermore, BaZrO 3 nanorods in REBa 2 Cu 3 O y (RE: rare-earth element) films are formed by self-assembled stacking of BaZrO 3 using a target mixture of a superconductor and BaZrO 3 for pulsed-laser deposition, which is a very easy fabrication technique. The density of BaZrO 3 nanorods in YBa 2 Cu 3 O y (YBCO) films can be controlled by varying the BaZrO 3 content in a target. The BaZrO 3 addition has two functions for superconductivity; one is the improvement of pinning forces due to the addition of pinning centers and the other is T c degradation. The optimum BaZrO 3 addition for J c improvement in magnetic fields is found to be around 3 wt% because of a trade-off between the two functions described above. Furthermore, the length of BaZrO 3 nanorods is found to be controlled using two types of target: pure YBCO and a mixture of YBCO and BaZrO 3. Varying the BaZrO 3 nanorod length has an effect on the pinning mechanism. In particular, magnetic field angle dependences of J c are varied from c-axis-correlated pinning to nearly random pinning by changing the nanorod length. The magnetic field at the crossover of the pinning mechanism seems to be adjusted by the BaZrO 3 nanorod length.