Elastic constants and charge ordering inα′−NaV2O5

Martensitic Transformation and Elastic Constants

Elastic constants of natural quartz.

The elastic constants of a natural-quartz sphere using resonance-ultrasound spectroscopy (RUS) are measured. The measurements of the near-traction-free vibrational frequencies of the sphere are matched with the predicted frequencies from the dynamic theory of elasticity, with optimized estimates for the elastic constants driving the differences between these sets of frequencies to a minimal val...

Second Order Elastic Constants, Third Order Elastic Constants, Pressure Derivatives of Second Order Elastic Constants and the Low Temperature Thermal Expansion of D-tin

The complex behaviour of metals under severe thermal and stress environments is influenced markedly by their elastic properties. Indeed the response of a material tc~ an applied stress is always determined by the elastic constants and their pressure derivatives. Furthermore, both the mechanical and thermodynamic equation;$ of state of a metal that contains dislocations require detailed knowledg...

Charge states of ions, and mechanisms of charge ordering transitions.

To gain insight into the mechanism of charge ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2M(n+)→M((n+1)+) + M((n-1)+), we (1) review and reconsider the charge state (or oxidation number) picture itself, (2) introduce new results for the putative charge ordering compound AgNiO2 and the dual charge state insulator AgO, and (3) analyze the cationi...

Multiferroicity due to charge ordering

In this contribution to the special issue on multiferroics we focus on multiferroicity driven by different forms of charge ordering. We will present the generic mechanisms by which charge ordering can induce ferroelectricity in magnetic systems. There is a number of specific classes of materials for which this is relevant. We will discuss in some detail (i) the perovskite manganites of the type...