Structure, microstructure and magnetic properties of Sr1-xCaxCrO3 (0 <= x <= 1)

The effect of the calcium concentration on the structural, microstructural and magnetic properties of Sr(1-x)CaxCrO3 with 0 <= x <= 1 has been studied. The compounds were prepared using high pressure and high temperature synthesis. X-ray diffraction shows that the samples evolve from the cubic Pm-3m space group for x = 0-0.2 to tetragonal I4/mcm for x = 0.4-0.5, then to the orthorhombic Pbnm space group for x = 0.6, 0.8 and 1.0. Electron diffraction and high-resolution transmission electron microscopy confirmed the respective cells for the end compositions: a(p) x a(p) x a(p) (Pm-3m) for SrCrO3; and the root 2a(p) x root 2a(p) x 2a(p) (Pbnm) for CaCrO3. For intermediate compositions some extra spots appear in the electron diffraction patterns while the electron micrographs indicate the presence of microdomains. Magnetic measurements show Curie-Weiss behaviour at high temperature for all the samples. A sharp antiferromagnetic (AFM) transition at about 91.5 K appears for x = 0.8-1 together with a weak ferromagnetic ordering below T-N. (c) 2008 Elsevier Inc. All rights reserved.