Superconducting NdBa/sub 2/Cu/sub 3/O/sub 7-δ/ thin films prepared by the laser ablation method

Abstract

Albstract-NdBa2Cu3O,-+NBCO) thin films were deposited on (100) SrTiO,(STO) substrates by the laser ablation method. The transition temperature of thin films was very sensitive to the deposition parameters such as substrate temperature, chamber pressure, and the distance between target and substrate. Thin film; of T, -93 K were obtained when we deposited at 770 "C and 800 mTorr of oxygen pressure. The NEICO thin films were grown epitaxially with c-axis preferred orientation. The critical current density of the thin films was -1 x lo6 Akm2 at 77 K.We have also studied the surface morphology with AFM, and the typical smoothness is -3 nm.

The mid-infrared dielectric function of NBCO in thea-bplane from 85 K to 300 K

“…However, films made by PLD are usually characterized by coarse grain structure and a particulate population consisting of outgrowths, droplets and often debris from the target. Comparative studies on PLD film growth, reported by several groups [5,6,[10][11][12][13], show that superior quality films, in terms of smoothness, crystallinity and stability, can be made with NBCO compared with YBCO. The optimization of the deposition depends on a complex interplay between many parameters, but the most important parameter, common to all the studies reported, appear to be the substrate temperature, the laser fluence on the target, the target composition and density, the substrate lattice parameter and surface morphology and the ambient oxygen pressure.…”

“…Thin films of high-temperature superconductors are now systematically made by a number of methods such as pulsed laser deposition (PLD) [5,[10][11][12][13], sputtering (rf and dc) [14,15] and by metal-organic chemical vapour deposition (MOCVD) [16]. PLD is the most widely used technique.…”