Numerical Simulation of Nanorod Growth in REBa2Cu3Oy Superconducting Thin Films

Various nanostructures consisting of BaMO
₃
(BMO) self-organize in REBa
₂
Cu
₃
Oy (REBCO) films prepared by vapor phase epitaxy. A numerical simulation of the BMO self-organization was developed using the three-dimensional Monte Carlo (3D-MC) method, and the effects of deposition parameters such as substrate temperature (T
_s
), deposition rate (v
_dep
), and BMO volume fraction (f
_BMO
) on BMO self-organization were investigated. We consider only the kinetic factors and ignore mismatch strain on the nanorods (NRs) morphology. 3D-MC simulations for various T
_s
indicated that the number density of BMO NRs decreased with an increase in T
_s
, and this tendency was similar to previous experimental results for BaHfO
₃
-doped SmBCO films prepared by the pulsed laser deposition method. The effects of v
_dep
and f
_BMO
were also simulated to provide contour plots of the number density of NRs with respect to T
_s
and f
_BMO
at various v
_dep
. Phase diagrams of nanostructures consisting of BMO with various v
_dep
were also obtained. Although these results do not take into account degradation of the superconducting properties and crystalline defects induced by nonoptimized conditions, they are considered to be a useful guideline for control of the flux pinning landscape on REBCO-coated conductors.