相关论文: Thermoelasticity of Fe$^{3+}$- and Al-bearing brid…

We present LDA+U calculations of high temperature elastic properties of bridgmanite with composition (Mg$_{(1-x)}$Fe$_{x}^{2+}$)SiO$_3$ for $0\le{x}\le0.125$. Results of elastic moduli and acoustic velocities for the Mg-end member (x=0)…

Fe and Al are two of the most important rock-forming elements other than Mg, Si, and O. Their presence in the lower mantle's most abundant minerals, MgSiO_3 bridgmanite, MgSiO_3 post-perovskite and MgO periclase, alters their elastic…

The primary phase of the Earth's lower mantle, (Al, Fe)-bearing bridgmanite, transitions to the postperovskite (PPv) phase at Earth's deep mantle conditions. Despite extensive experimental and ab initio investigations, there are still…

The spin crossover of iron in Fe$^{3+}$-bearing bridgmanite, the most abundant mineral of the Earth's lower mantle, is by now a well-established phenomenon, though several aspects of this crossover remain unclear. Here we investigate…

We have studied the ferrous (Fe2+) and ferric (Fe3+) iron concentrations in Al-free Fe containing Mg-silicate perovskite (Mg-Pv) at pressure (P), temperature (T), and oxygen fugacity (fO2) conditions related to the lower mantle using a…

Earth's lower mantle is generally believed to be seismically and chemically homogeneous because most of the key seismic parameters can be explained using a simplified mineralogical model at expected press-temperature conditions. However,…

Iron partitioning among the main lower mantle phases, bridgmanite (Bm) and ferropericlase (Fp), has non-monotonic behavior owing to the high-spin to low-spin crossover in ferrous iron (Fe2+) in Fp. Results of previous studies of the iron…

We report a comprehensive study of the temperature-dependent structural, magnetic, vibrational, and dielectric properties of Al-substituted M-type hexaferrites SrFe$_{12-x}$Al$_x$O$_{19}$. Neutron powder diffraction and M\"ossbauer…

The addition of transition metal elements can significantly modify physical properties of intermetalic compounds. We studied the influence of Molybdenum and Vanadium additives on thermal expansion coefficient (CTE) of Fe/sub 3/Al and FeAl…

BaFe$_2$S$_3$ is a quasi-one-dimensional antiferromagnetic insulator that becomes superconducting under hydrostatic pressure. The magnetic ordering temperature, $T_N$, as well as the presence of superconductivity have been found to be…

Iron spin transition directly affects properties of lower mantle minerals and can thus alter geophysical and geochemical characteristics of the deep Earth. While the spin transition in ferropericlase has been vigorously established at P ~…

The iron spin crossover in ferropericlase introduces anomalies in its thermodynamics and thermoelastic properties. Here we investigate how these anomalies can affect the lower mantle geotherm. The effect is examined in mantle aggregates…

Ferromagnesite (Mg,Fe)CO3, also referred to as magnesiosiderite at high iron concentration, is a solid solution of magnesite (MgCO3) and siderite (FeCO3). Ferromagnesite is believed to enter the Earth's lower mantle via subduction and is…

PbTiO3 has the highest tetragonal distortion (c/a=1.064) and highest spontaneous polarization among perovskite titanates. But, it is hazardous and hence one needs to reduce Pb content by substituting or reducing Pb content for use in…

Ferroelasticity describes a phenomenon in which a material exhibits two or more equally stable orientation variants and can be switched from one form to another under an applied stress. Recent works have demonstrated that two-dimensional…

The elastic and magnetic properties, thermodynamical stability, deviation from stoichiometry and order/disorder transformations of phases that are relevant to Be alloys were investigated using density functional theory simulations coupled…

Here, we provide a reappraisal of potential LLSVPs compositions based on an improved mineralogical model including, for instance, the effects of alumina. We also systematically investigate the effects of six parameters: FeO and…

Experimental and theoretical studies of unusual polar, dielectric and magnetic properties of room temperature multiferroics, such as perovskites Pb(Fe$_{1/2}$Nb$_{1/2}$)O$_3$ (PFN) and Pb(Fe$_{1/2}$Ta$_{1/2}$)O$_3$ (PFT), are very…

The structural, electronic and magnetic properties of Fe7S8 material have been studied within the framework of the ab-initio calculations, the mean field approximation (MFA) and Monte Carlo simulation (MCS). Our study shows that two forms…

In this study, we considered a large set of materials that are closely related to orthorhombic Fe$_3$C (cementite) with the aim of characterizing trends in their intrinsic magnetic properties and identifying alloys that are optimal for…