Raman scattering spectroscopy of Nd1+xBa2-xCu3O7 coated conductors grown by pulsed laser deposition

초록

We analyzed Nd1+xBa2-xCu3O7 (NdBCO) coated conductors grown at various substrate temperatures by using Raman spectroscopy. Epitaxial NdBCO films were deposited on ion beam assisted deposition yttrium stabilized zirconia (IBAD-YSZ) templates by pulsed laser deposition. Raman scattering spectroscopy shows that the NdBCO film grown at a relatively low substrate temperature of 750 degrees C contains some a-axis oriented grains as well as c-axis oriented grains and an excess cation disorder between Nd3+ ions and Ba2+ sites, which result in degradation of superconducting properties with critical temperature (T-c) of similar to 83 K and critical current density (J(c)) of less than 1 MA cm(-2) at 77 K and self-field. The samples grown at higher temperatures ranging from 775 to 800 degrees C are found to have strong c-axis orientation with little cation disorder, and subsequently excellent superconducting properties with T-c of 88-90 K and J(c) of 1.2-1.8 MA cm(-2) at 77 K and self-field.

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