Physical Review B (Condensed Matter) -- July 1, 1997
Volume 56, Issue 1, pp. 1-4

Equation of state of MgAl[sub 2]O[sub 4] spinel to 65 GPa

: M. B. Kruger
: Department of Physics, University of Missouri, Kansas City, Missouri 64110

: J. H. Nguyen
: Department of Physics, University of California, Berkeley, California 94720

: W. Caldwell and R. Jeanloz
: Department of Geology and Geophysics, University of California, Berkeley, California 94720

Compression measurements on synthetic MgAl[sub 2]O[sub 4] spinel, obtained by quasihydrostatic x-ray powder diffraction at room temperature, are in good agreement with ultrasonically determined values of the bulk modulus and its pressure derivative at zero pressure. Contrary to previous extrapolations of the ultrasonic data, from which an elastic (volume) instability had been predicted at ~25 GPa, our results show that the spinel structure is (meta)stable from 0 to 65 GPa. The zero-pressure values of the bulk modulus and its pressure derivatives which best fit all the available data are K[sub 0]=196((plus-minus)1) GPa, K[sub 0][sup (prime)]=4.7((plus-minus)0.3), and K[sub 0]K[sub 0][sup (double-prime)](approximate)-6.

History	Received: 5 February 1997
Subject	Equations of state, phase equilibria, and phase transitions
PACS	CODE: 64.30.+t Equations of state, phase equilibria, and phase transitions : Equations of state of specific substances CODE: 62.50.+p Mechanical and acoustical properties of condensed matter : High-pressure and shock-wave effects in solids and liquids CODE: 61.10.Nz Structure of solids and liquids; crystallography : X-ray diffraction and scattering : [Single-crystal and powder diffraction] YEAR: 1996
Keywords	magnesium compounds; equations of state; high-pressure effects; X-ray diffraction; elastic moduli
Doc. Type	Experimental; Brief Reports
Coden	PRBMDO
PII	S0163-1829(97)05026-1

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