Irreversible properties of YBCO thick films deposited by liquid phase epitaxy on single crystalline substrates

Abstract

We report on the field and temperature dependence of the critical transport current density J c , the angular dependence of the transport current at various external magnetic fields and the irreversibility fields in YBa 2 Cu 3 O 7−δ (Y-123) thick films prepared by liquid phase epitaxy (LPE). A comparison of the irreversible properties between specimens produced with and without silver additions to the melt is also presented. Transmission electron microscopy (TEM) was employed to obtain information on the correlation between the transport properties and the microstructure. The samples were deposited either directly on NdGaO 3 (NGO) or on seeded (100) MgO substrates, where a 200 nm thin YBCO film deposited by pulsed laser deposition (PLD) acts as seed layer for the LPE process. The final thickness of the Y-123 layer is of the order of 1 µm for the NGO and between 2 and 10 µm for the MgO samples. The critical current densities reach 3 × 10 9 A m −2 at zero field and 77 K in the best case.

The Orientation Transition and Control of REBaCu3Oy Films Grown by Liquid Phase Epitaxy

“…Accordingly, the superconducting performance of the YBCO c -films with and without a -grains were measured, with the T c value equal to 88.7 and 85.2 K for the former and latter samples, respectively. Note that the results obtained in that work are comparable to the references, ,, but slightly lower than that of typical Y123 superconductors (92 K), due to the contamination from NGO substrates at high temperature during the film growth. J c –H curves of the two samples measured under liquid nitrogen temperature were shown in Figure , which are comparable to other reports employing the same substrates. , Particularly, the highest J c value at 0 T is 4.57 × 10 3 and 0.73 × 10 3 A/cm 2 for c -films with and without a -axis grains, respectively.…”