New ferromagnets of Sr(8)ARe(3)Cu(4)O(24) (A = Sr, Ca) with an ordered perovskite structure

New phases Sr(8)ARe(3)Cu(4)O(24) (A = Sr,Ca) were discovered under high-pressure/high-temperature condition. X-ray powder diffraction and electron diffraction studies for these phases indicated that they have an ordered perovskite-type structure with cubic lattices of similar to 8 Angstrom. They showed ferromagnetism at room temperature when they were synthesized under high-oxygen-pressure condition. The Ca-containing phase has a very high T-c of 440 K with a spontaneous magnetization of similar to 1 mu(B)/f.u. (C) 2003 Elsevier Inc. All rights reserved.