Ground State of Divalent Co Ions in Cs3CoCl5 and Cs3CoBr5

Abstract

The 4A2 ground state of tetrahedrally coordinated divalent cobalt ions in Cs3CoCl5 and Cs3CoBr5 is investigated with magnetic-susceptibility measurements and paramagnetic resonance in pulsed magnetic fields up to 90 kOe at frequencies in the 70- and 120-Gc/sec bands. The first excited state (4T2) which lies ∼3000 cm−1 above the ground state is studied optically on Cs3Zn0.9Co0.1Cl5. The sign of the splitting of the 4T2 state is opposite to that expected from the observed negative zero-field splitting of the ground state.

Magnetic phase diagram and first-principles study ofPb3TeCo3V2O14

“…We note that these exchange constants were obtained for the crystal structure presented in Ref. 13, an additional distortions proposed in Ref. 5 may modify these results.…”

“…However, the estimated from Lorenzian fit g values g ⊥ ≈ 2.13 and g || ≈ 3.10 are in reasonable agreement with the experimental values observed for other compounds with Co 2+ ions in tetrahedral coordination. [11][12][13] Evidently, the ESR line is characterized by practically temperature-independent effective gfactors with an average value g = (2g ⊥ + g || )/3 = 2.45 ± 0.05. A rough estimation for an exchange anisotropy according to expression J ⊥ /J || = g ⊥ /g || 14 yields a value J ⊥ /J || ~ 0.7 indicating moderate anisotropy in Pb 3 TeCo 3 V 2 O 14 .…”

Electron density distribution in Cs3CoCl5

“…These studies reveal no phase change and so conform with heat capacity (Wielinga, Blote, Roest & Huiskamp, 1967), magnetic (Figgis, Gerloch & Mason, 1964b;Van Stapele, Beljers, Bongers & Zijlstra, 1966;Mess, Lagendijk, Curtis & Huiskamp, 1967), ESR (Van Stapele et al, 1966;Beljers, Bongers, Van Stapele & Zijlstra, 1964) and optical spectroscopy (Bird, Cooke, Day & Orchard, 1974;Pelletier-Allard, 1964) measurements.…”

Structural properties of two inequivalent Cs(1) and Cs(2) sites in perovskite tricaesium pentahalogencobaltate, Cs3CoX5 (X = Cl, Br)

“…26 Cs 3 CoCl 5 and Cs 3 CoBr 5 crystals have very similar structures, space groups, lattice parameters, and bond lengths, as shown in Table I. 15,25,27,28 A Co 2+ ion in a Cs 3 CoX 5 crystal is surrounded by four X ions that form a tetrahedron that is slightly elongated along the c-axis. Figs.…”