High-voltage high-resolution electron microscopy study of alkaline-earth copper oxides.
Two families of alkaline-earth copper oxides are studied by using high-voltage high-resolution electron microscopy. One is Sr(n-1) Cu(n)O(2n-1) (n = 2, 3), the so-called spin-ladder compounds, and the other is ACuO2 (A = Ca-Sr) crystallizing in the infinite-layer structure, which is a parent structure for all copper oxide superconductors. It is demonstrated in the former compounds that oxygen columns as well as metal columns are directly imaged in a "structure" image. Moreover, twin-related lattice defects, which can be the origin of free Cu2+ spins observed previously in magnetic measurements, have been detected in SrCu2O3. An interesting irradiation effect under a 1,000-kV electron beam has been observed in the infinite-layer compound: An unusual structural phase transformation to a NaCl-type lattice is induced, accompanied by the formation of nm-size twin domains.
Hiroi
Z
Z
Institute for Chemical Research, Kyoto University, Japan. hiroi@scl.kyoto-u.ac.jp
Horiuchi
S
S
D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D007091:Image Processing, Computer-Assisted; D008673:Metals, Alkaline Earth / Q000737:chemistry*; D008854:Microscopy, Electron; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen; D013324:Strontium / Q000737:chemistry
D008673:Metals, Alkaline Earth; D010087:Oxides; D003300:Copper; D010100:Oxygen; D013324:Strontium