Magnetic and Structural Properties of the 'Brown Phase' Solid Solution Ba(Nd2-xLax)CuO5

Published

July 1, 2003

Author(s)

Winnie K. Wong-Ng, L Swartzendruber, James A. Kaduk, Lawrence H. Bennett

Abstract

The compounds BaR₂CuO₅ (R = Y, and lanthanides) are well known impurities that often coexist with the high T_c superconductors, Ba₂RCu₃O_6+X. With R=La and Nd, brown color solid solutions (Ba_1+xR_2-xCuO_5-x) form instead of the green phase, BaR₂CuO₅ (lanthanides with ionic radii smaller than that of Sm). A complete solid solution of Ba(Nd_2-xLa_xCuO₅ exists with the tetragonal space group P4/mbm. Crystallographic studies of selected members (x=0.2, 0.6, 1.2, and 1.6) by x-ray Rietveld refinement technique showed the structure consists of RO₈ and BaO₁₀ cages, and square planar CuO₄ units. As x increases in Ba(Nd_2-xLa_x)CuO₅, the size of these RO₈ and BaO₁₀ cages increases. BaLa₂CuO₅ was confirmed to be ferromagnetic at 5K; despite the isostructural property of BaLa₂CuO₅ and BaNd₅CuO₅, the Nd-analog was found to be antiferromagnetic. As x in Ba(Nd_2-xLa_x)CuO₅ increases between 0 and 2, the amount of ferromagnetism increases.

Citation

Physica C-Superconductivity and Its Applications

Volume

390

Issue

No. 3

Pub Type

Journals

Keywords

Ba(Nd_2-xLa_x)CuO₅, brown phase, magnetic properties, superconductor related phase

Citation

Wong-Ng, W. , Swartzendruber, L. , A., J. and Bennett, L. (2003), Magnetic and Structural Properties of the 'Brown Phase' Solid Solution Ba(Nd_2-xLa_x)CuO₅, Physica C-Superconductivity and Its Applications (Accessed October 14, 2025)