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Article Dans Une Revue The American Mineralogist Année : 2006

Equation of state and phase transition in KAlSi3O8 hollandite at high pressure

Tsuyoshi Onozawa
  • Fonction : Auteur
Takehiko Yagi*
  • Fonction : Auteur
Sebastien Merkel
Nobuyoshi Miyajima
  • Fonction : Auteur
Takumi Kikegawa
  • Fonction : Auteur

Résumé

The tetragonal hollandite structure (KAlSi3O8 hollandite) has been studied up to 32 GPa at room temperature using high-pressure in-situ X-ray diffraction techniques. A phase transformation from tetragonal I4/m phase to a new phase was found to occur at about 20 GPa. This transition is reversible on release of pressure without noticeable hysteresis and hence this new high-pressure phase is unquenchable to ambient conditions. The volume change associated with the transition is found to be small (not measurable), suggesting a second order transition. The diffraction pattern of the high-pressure phase can be indexed in a monoclinic unit cell (space group I2/m), which is isostructual with BaMn8O16 hollandite. The {gamma} angle of the monoclinic unit cell increases continuously above the transition. A Birch-Murnaghan equation of state fit to pressure-volume data obtained for KAlSi3O8 hollandite yields a bulk modulus K0 = 201.4 (7) GPa with K'0 = 4.0.

Domaines

Minéralogie
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Dates et versions

hal-00095209 , version 1 (15-09-2006)

Identifiants

Citer

Tristan Ferroir, Tsuyoshi Onozawa, Takehiko Yagi*, Sebastien Merkel, Nobuyoshi Miyajima, et al.. Equation of state and phase transition in KAlSi3O8 hollandite at high pressure. The American Mineralogist, 2006, 91, pp.327-332. ⟨10.2138/am.2006.1879⟩. ⟨hal-00095209⟩
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