CoO has an odd number of electrons in its unit cell, and therefore is expected to be metallic. Yet, CoO is strongly insulating owing to significant electronic correlations, thus classifying it as a Mott insulator. We investigate the magnetic fluctuations in CoO using neutron spectroscopy. The strong and spatially far-reaching exchange constants reported in [Sarte et al. Phys. Rev. B 98 024415 (2018)], combined with the single-ion spin-orbit coupling of similar magnitude [Cowley et al. Phys. Rev. B 88, 205117 (2013)] results in significant mixing between j eff spin-orbit levels in the low temperature magnetically ordered phase. The high degree of entanglement, combined with the structural domains originating from the Jahn-Teller structural distortion at ∼ 300 K, make the magnetic excitation spectrum highly structured in both energy and momentum. We extend previous theoretical work on PrTl3 [Buyers et al. Phys. Rev. B 11, 266 (1975)] to construct a mean-field and multi-level spin exciton model employing the aforementioned spin exchange and spin-orbit coupling parameters for coupled Co 2+ ions on a rocksalt lattice. This parameterization, based on a tetragonally distorted type-II antiferromagnetic unit cell, captures both the sharp low energy excitations at the magnetic zone center, and the energy broadened peaks at the zone boundary. However, the model fails to describe the momentum dependence of the excitations at high energy transfers, where the neutron response decays faster with momentum than the Co 2+ form factor. We discuss such a failure in terms of a possible breakdown of localized spin-orbit excitons at high energy transfers. arXiv:1908.00459v2 [cond-mat.str-el] 2 Aug 2019Motivated by previous work on PrTl 3 27,58 , the theoretical portion of this paper begins by first writing down the equations-of-motion for the response function in terms of commutators involving the magnetic HamiltonianĤ. We

Neutron spectroscopy was applied to study the magnetic interactions of orbitally degenerate Co 2+ on a host MgO rocksalt lattice where no long range spin or orbital order exists. The paramagnetic nature of the substituted monoxide Co0.03Mg0.97O allows for the disentanglement of spin-exchange and spin-orbit interactions. By considering the prevalent excitations from Co 2+ spin pairs, we extract 7 exchange constants out to the fourth coordination shell. An antiferromagnetic next nearest neighbor 180 • exchange interaction is dominant, however dual ferromagnetic and antiferromagnetic interactions are observed for pairings with other pathways. These interactions can be understood in terms of a combination of orbital degeneracy in the t2g channel and the Goodenough-Kanamori-Anderson (GKA) rules. Our work suggests that such a hierarchy of exchange interactions exists in transition metal-based oxides with a t2g orbital degeneracy.

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Intravenous lipid emulsion (ILE) has been demonstrated to be an effective treatment for systemic toxicity associated with local anaesthetics and increasingly non-local anaesthetic agents of high lipophilicity. Effect for ILE has been demonstrated in animal models of propranolol poisoning; however, any benefit for ILE in more hydrophilic β-blockers remains uncertain. We determined to examine the effect of ILE on haemodynamic recovery following induction of hypotension with the relatively hydrophilic β-blocker, metoprolol. Twenty sedated, invasively monitored and mechanically ventilated adult New Zealand white rabbits underwent metoprolol infusion to mean arterial pressure (MAP) 60% baseline. Intravenous rescue was given according to the following groups: 6 mL/kg 20% lipid emulsion or 6 mL/kg 0.9% saline solution over 4 min. Haemodynamic parameters were obtained in 15 min. MAP was 70 (interquartile range (IQR), 58-82) mmHg saline group and 79 (IQR,(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83)(84)(85)(86)(87)(88)(89) mmHg ILE group at baseline, and 38 (IQR, 33-40) mmHg saline group and 41 (IQR, 40-43) mmHg ILE group, respectively, following metoprolol infusion. No statistically significant difference between ILE and saline-treated groups was observed in MAP, or pulse rate, at any time point following rescue therapy. ILE was not effective in reversal of metoprolol-induced hypotension in this rabbit model. These findings lend inferential support for the 'lipid sink' as principal mechanism for the beneficial effect observed with ILE administration in other models of lipophilic β-blocker-induced toxicity.

The structures and properties of vanadium oxides are often related to the formation of molecule-like clusters of vanadium cations through direct V-V bonding. GaVO, a new vanadium spinel, was synthesized. Powder diffraction and X-ray total scattering studies, complemented by magnetization and resistivity measurements, reveal that the low-temperature phase of this material is structurally distorted and features ordered pairs of three- and four-atom vanadium clusters. These clusters persist into a disordered cubic phase above the charge-ordering transition at T = 415 K. Furthermore, quasi-elastic neutron scattering indicates that the disordered clusters remain well-defined and static to 1100 K.