Pressure and temperature dependence of the elastic properties of synthetic MnO

Abstract

Abstract. The adiabatic elastic stiffness constants of synthetic single-crystal MnO were measured in this study using pulse superposition interferometry. Data were obtained up to 1.0 GPa in pressure and over the temperature range 273 to 473 K. As a result, we were able to determine the complete set of second-order stiffness moduli (C~]) and their pressure and temperature derivatives, as well as higher-order properties for selected modes. Relevant results for the adiabatic bulk modulus are: KS= 155.1 +0.8 GPa;(~Ks/~P)r=4.70+_0.13; and, (~KS/~T)v=-0.0203_+0.0009 GPa/K. Our results for the second-order moduli are generally consistent with the data from previous studies. However, relative to the estimated uncertainties, small and systematic discrepancies appear to characterize the data set. The available evidence indicates that the differences result from microstructural variations (in particular, microcracks and Mn30 4 inclusions) between the synthetic MnO specimens used in different investigations. The pure shear mode C44 exhibits anomalous soft-mode behavior with both temperature (the ambient derivative is positive) and pressure (the ambient derivative is negative). In both cases the C4~ data trends appear to primarily reflect the influence of Mn -Mn magnetoelastic interactions associated with the onset of a paramagnetic-antiferromagnetic (PM --> AFM) phase transition.

Raman spectra of natural manganese oxides

“…Nevertheless Raman spectra, although with some discrepancies, are commonly reported in literature . Raman active modes could result from a small rhombohedral distortion that occurs to the onset of the paramagnetic‐antiferromagnetic phase transition, at room pressure and from ~330 K toward the Néel point of MnO (118 K) . Also Jahn–Teller effect and/or structural defects could locally lead to the decrease of the averaged symmetry.…”

Active Mixed‐Valent MnOx Water Oxidation Catalysts through Partial Oxidation (Corrosion) of Nanostructured MnO Particles

“…Simulation of the spectra was performed with two oxygen shells, and with seven MnMn distances (SI, Table S1). The first MnO distance (1.9 Å) is typical for Mn IV O or Mn III O in the equatorial plane of Jahn–Teller elongated Mn III ,20 and the second (2.3 Å), for Mn II O 21. The longer MnO distance can also be attributed to Jahn–Teller elongated Mn III O bonds (species with t 2g 3 e g 1 electronic configuration in octahedral environment) 18…”

Poisson's Ratio and Auxetic Properties of Natural Rocks

“…Poisson's ratio‐density plots for 153 oxides. Experimental data were compiled from the following references: Akimoto (), Albers and Boeyens (), Anderson et al (), Anderson and Isaak (), Antao et al (), Bass (), Berger et al (), Berlincourt and Jaffe (), Chang and Barsch (), Chang and Graham (), Chung (, , ), Cohen (), Duffy and Ahrens (), Fischer et al (), Fritz (), Fujisawa et al (), Funamori et al (), Gieske and Barsch (), Goto et al (), Hama and Suito (), Hearmon (), Higo et al (), Horiuchi and Sawamoto (), Iishi (), Isaak et al (), Jackson et al (), Jackson and Khanna (), Jackson and Niesler (), Johnston et al (), Karki et al (), Karki and Crain (), Kobiakov (), Kung et al (), Kung et al (), Lakshtanov et al (), Li et al (), Li and Zhang (), Liebermann (), Liebermann et al (), Liebermann and Maasch (), Liebermann and Ringwood (), Liebermann and Schreiber (), Manghnani (), Matsui et al (), Mizutani et al (), Notis et al (), Oda et al (), Ohno et al (), Ohno et al (), Oliver (), Pacalo and Graham (), Peercy et al (), Peselnick and Meister (), Reichmann and Jacobsen (), Reichmann and Jacobsen (), Rossi and Lawrence (), Schreiber (), Schreiber and Anderson (), Simmons and England (), Sinogeikin an...…”