Superconducting transition temperature of NdBCO liquid phase epitaxy film on MgO substrate and effect of Mg diffusion

NdBCO thick films were grown by liquid phase epitaxy (LPE) for the electronic device substrates. To optimize the process for achieving high critical transition temperature (Tc), different oxygenation conditions were applied. At 250°C held for 200 h in the oxygen gas atmosphere, the high Tco of NdBCO LPE film was achieved at 91 K with a sharp transition, which is lower than the reported maximum value of nearly 95 K for the NdBCO system. The contamination of Mg from the MgO substrate to the RE123 film plays a significant role in the Tc reduction. The Mg diffusion coefficient DMg in NdBCO and its relation with temperature were deduced.