Abstract
Spontaneous self-assembly of a multi-cation nanophase in another multi-cation matrix phase is a promising bottom-up approach to fabricate novel, nanocomposite structures for a range of applications. In an effort to understand the mechanisms for such self-assembly, we report on complimentary experimental and theoretical studies to first understand and then control or guide the self-assembly of insulating BaZrO3 (BZO) nanodots within REBa2Cu3O7-δ (RE=rare earth elements including Y, REBCO) superconducting films. It was determined that the strain field developed around BZO nanodots embedded in REBCO matrix is a key driving force dictating the self-assembly of BZO nanodots along REBCO c-axis. The size selection and spatial ordering of BZO self-assembly were simulated using thermodynamic and kinetic models. The BZO self-assembly was controllable by tuning the interphase strain field. REBCO superconducting films with BZO defects arrays self-assembled to align in both vertical (REBCO c-axis) and horizontal (REBCO ab-planes) directions, resulted in the maximized pinning and Jc performance for all field angles with smaller angular Jc anisotropy. The work has broad implications for fabrication of controlled self-assembled nanostructures for a range of applications via strain-tuning.
