Titlebook: Structural and Magnetic Phase Transitions in Minerals; S. Ghose,J. M. D. Coey,E. Salje Conference proceedings 1988 Springer-Verlag New Yor

Duodenitis

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使害怕

Molecular Dynamics Studies of Polymorphism of SiO2 at High Pressures: A Possible New Cubic Polymorpst-principles calculations on SiO. with the fluorite structure have been carried out by Hemley .. (1985) and Bukowinski and Wolf (1986). Their results indicate that the SiO.-fluorite phase may be at least metastable provided the pressure is extremely high; and below the critical pressure, 160 GPa ac

MITE

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CHIP

declamation

The Spin Glass State in Garnet Mixed Crystals: New Evidence from Neutron Scattering and MacroscopicD’s are anions, mostly oxygen or fluorine. The structure consists of isolated CD. tetrahedra, e.g., SiO. in the case of naturally occurring minerals. The A ions are surrounded by a distorted octahedron, properly speaking by a trigonal antiprism, and the B ions by 12 neighbors forming orthorhombic bi

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Polytypism and Equilibrium Phase Transitions: In Situ Observation of the Polytypic Phase Transitionquences. This effect is usually called “polytypism.” Its structural features have been thoroughly studied in compounds like SiC, CdI., sulfides, several alloys, and many minerals. The physical reason for the formation of polytypic phases, however, is far from understood. Several models have been dis

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Molecular Dynamics Studies of Polymorphism of SiO2 at High Pressures: A Possible New Cubic Polymorped out an extensive calculation of the stability of various possible polymorphs of SiO., including those with rutile, α-PbO., “defect NiAs,” baddeleyite, and fluorite structures. They concluded that the SiO.-fluorite and the SiO.-baddeleyite are less stable than SiO.-rutile even under extremely high-pressure conditions.

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Incommensurate Phase Transitions in Quartz and Berlinite,hase to the high-temperature β phase. Since its discovery by Le Chatelier (1889), this transition has been the subject of so many investigations that one would expect its properties to be well known. It is, therefore, quite surprising to find that some uncertainties remain even about basic propertie