Controlled BaMO₃ (M=Zr, Hf, Sn etc) nanorods (NRs) using pulsed laser deposition (PLD) have been shown to have great success in improving superconducting performance [1] in REBa₂Cu₃O_y (REBCO) superconducting films. However, for the PLD films, the c-axis length of REBCO matrix lattice expands markedly with increasing vol.% of BMO dopant because the interface between BMO NR and matrix is coherent [2]. The expanded c-axis affects superconducting properties such as matrix crystallinity, critical temperature (T_c) and self-field critical current density (J_c). To be effective, morphology (shape, size and density) has to be tuned with little degradation of the matrix crystallinity, carrier density and T_c.

We show how it is possible to tune to obtain morphology of BHO while maintaining the crystallinity of the REBCO matrix deposited by growth-condition controlled RTR-PLD. We get significant enhancement of the in-field J_c for PLD-REBCO+BHO coated conductors over a broad temperature and field-angle range by changing the growth conditions. The enhancement of in-field J_c are seen not only at low temperatures but also at high temperatures. Detailed microstructural and superconducting properties for nanocomposite PLD-REBCO CCs will be presented.

Acknowledgements: This work at Seikei University was supported by JST-FOREST (Grant Number JPMJFR202G). This work at AIST was supported by the New Energy and Industrial Technology Development Organization (NEDO).

Reference: [1] B. Maiorov et al., Nature Materials 8 (2009) 398.  [2] M. Miura et al., NPG Asia Materials 9 (2017) e447.

Keywords: Critical Current, Flux Pinning, RTR-PLD, Coated Conductor