Surface Analysis of Ln(2-x)Ce(x)CuO4 (Ln = Pr and Nd) Single Crystals Grown by the Top Seeded Solution Method
Abstract
Large single crystals of Ln2-xCexCU04 (Ln = Pr and Nd), the average size is approximately 5 mm x 5 mm x 1 mm, were grown by the Top Seeded Solution Growth (TSSG) technique. The optical constants of the crystals were determined by Variable Angle Spectroscopic Ellipsometry (VASE) and the results seem to indicate that a 1.5 eV absorption peak appears in the undoped material and is weakened and shifted downward in energy upon annealing. The compositions and crystal structure were examined using Rutherford Backscattering Spectroscopy (RBS) with ion beam channeling. Also, the effect of annealing on the crystalline structure was probed by ion beam channeling. The orientation and lattice parameters of the crystals were determined by X-ray diffraction and the superconductivity of the specimens was monitored using a SQUID magnetometer. The results indicate that the crystals grown by the TSSG method are very uniform in composition and well-oriented; however, analysis of the RBS data indicated up to 1% Pt inclusion in the crystals from contact with the Pt crucibles. The inclusion of Pt acted to quench the superconducting transition temperatures and Pt was found to substitute for Cu.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1992
- Accession Number
- ADA254905
Entities
People
- J. D. Demaree
- Louise C. Sengupta
- Somnath Sengupta
- Wendy E. Kosik