77 research outputs found
Structure Determination of Ba\u3csub\u3e8\u3c/sub\u3eCoRh\u3csub\u3e6\u3c/sub\u3eO\u3csub\u3e21\u3c/sub\u3e, a New Member of the 2H-Perovskite Related Oxides
Single crystals of Ba8CoRh6O21 were grown out of a potassium carbonate flux. The structure was solved by a general method using the superspace group approach. The superspace group employed was R3m(00γ)0s with a = 10.0431(1) Å, c1 = 2.5946(1) Å and c2 = 4.5405(1) Å, V = 226.60(1) Å3. Ba8CoRh6O21 represents the first example of an m = 5, n = 3 member of the A3n+3mA\u27nB3m+nO9m+6n family of 2H hexagonal perovskite related oxides and contains chains consisting of six consecutive RhO6 octahedra followed by one distorted CoO6 trigonal prism. These chains in turn are separated from each other by [Ba]∞ chains
Crystal structure, electronic, and magnetic properties of the bilayered rhodium oxide Sr3Rh2O7
The bilayered rhodium oxide Sr3Rh2O7 was synthesized by high-pressure and
high-temperature heating techniques. The single-phase polycrystalline sample of
Sr3Rh2O7 was characterized by measurements of magnetic susceptibility,
electrical resistivity, specific heat, and thermopower. The structural
characteristics were investigated by powder neutron diffraction study. The
rhodium oxide Sr3Rh2O7 [Bbcb, a = 5.4744(8) A, b = 5.4716(9) A, c = 20.875(2)
A] is isostructural to the metamagnetic metal Sr3Ru2O7, with five 4d electrons
per Rh, which is electronically equivalent to the hypothetic bilayered
ruthenium oxide, where one electron per Ru is doped into the Ru-327 unit. The
present data show the rhodium oxide Sr3Rh2O7 to be metallic with enhanced
paramagnetism, similar to Sr3Ru2O7. However, neither manifest contributions
from spin fluctuations nor any traces of a metamagnetic transition were found
within the studied range from 2 K to 390 K below 70 kOe.Comment: To be published in PR
Specific heat and magnetization study on single crystals of a frustrated, quasi one-dimensional oxide: Ca3Co2O6
Specific heat and magnetization measurements have been carried out under a
range of magnetic fields on single crystals of Ca3Co2O6. This compound is
composed of Ising magnetic chains that are arranged on a triangular lattice.
The intrachain and interchain couplings are ferromagnetic and
antiferromagnetic, respectively. This situation gives rise to geometrical
frustration, that bears some similarity to the classical problem of a
two-dimensional Ising triangular antiferromagnet. This paper reports on the
ordering process at low-T and the possibility of one-dimensional features at
high-T.Comment: 7 pages, 6 figures, accepted for publication in PR
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