Abstract
New layered Co oxides of nominal formula Sr2(Ln0.8Ca0.2) Co2O6 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, and Y) are reported. Single-phase polycrystalline samples were obtained at compositions Sr2Y1-xCaxCo2.5+ 2O6-δ (0.2 ≤ x ≤ 0.5; 0 ≤ δ ≤ 0.24), Sr2Y1-xCaxCo3.4+2O 6+δ′ (0.2 ≤ x ≤ 0.5; 0.62 ≤ δ′ ≤ 0.79), and Sr2Dy0.8Ca0.2Co2O6.09. Powder X-ray and neutron diffraction, thermogravimetric analysis, magnetic susceptibility, and ac resistivity measurements were used to characterize the samples. The tetragonal unit cell for Sr2Y0.8Ca0.2Co2O6.00 (I4/mmm; a = 3.82765(6) Å, and c = 19.5795(3) Å) is comparable to that of the double layer superconducting copper oxide La2-xSrxCaCu2 O6. A long-range antiferromagnetic (AF) ordered state below about 300 K is found for Sr2Y1-xCaxCo2.5+2O 6-δ, and a magnetically glassy state below about 40 K for the oxidized AF phases. All materials are electrically insulating.
Original language | English (US) |
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Pages (from-to) | 277-286 |
Number of pages | 10 |
Journal | Journal of Solid State Chemistry |
Volume | 146 |
Issue number | 1 |
DOIs | |
State | Published - Aug 1999 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry
Keywords
- Kohlrausch law
- LaSrCaCuO
- Layered structure
- Spin glass
- Sr(Ln, Ca)CoO