ИСТИНА

An industrial R&D programme is ongoing at SuperOx, aimed at improving 2G HTS wire performance in magnetic fild. We introduce perovskite artifiial pinning centres into the HTS layer matrix. In contrast to most studies described in the literature, we use the high rate production processing parameters and PLD equipment at SuperOx Japan. Ths paper reports the results of Phase 1 of this programme. We fabricated 2G HTS wires using GdBCO PLD targets with 0-7% (wt.) BaZrO3 or BaSnO3 at 100, 150 and 200 Hz frequency. Th crystal structure and texture parameters of the HTS layer and perovskite inclusions were characterised with XRD. Th HTS layer microstructure and morphology were studied with TEM. Th angular dependencies of the critical current of the samples were measured by 4-probe transport technique at 77 and 65 K in 1 T magnetic fild and derived from magnetic hysteresis curves measured in PPMS in the 4.2-77 K temperature range and 0-9 T magnetic fild range. BaZrO3 and BaSnO3 formed column-shaped semi-coherent nano-inclusions in the GdBCO fim matrix. Th typical transverse size of the nano-columns was about 5 nm, and their volume density correlated with the dopant concentration. All doped samples exhibited much lower angular anisotropy of in-fild critical current and higher lif factors than undoped samples. Doped samples demonstrated higher minimum critical current for all fild orientations than undoped samples at 65 K and at lower temperatures. Thse results are an encouraging start of our programme, as they show a positive impact of artifiial pinning centres introduced into 2G HTS wires fabricated at production throughput. Future work will be focussed on the optimisation of PLD growth parameters, in order to maximise the improvements in specifi temperature and fild conditions, as well as on the verifiation of reproducibility of the improvements in production wires.