Effect of dilution on the spin pairing transition in rhombohedral carbonates
Journal Article
·
· High Pressure Res.
- UNLV
The compressibility of an iron-bearing magnesite (Mg{sub 0.87}Fe{sub 0.12}{sup 2+}Ca{sub 0.01}) CO{sub 3} was determined by means of single crystal diffraction up to 64 GPa. Up to 49 GPa the pressure-evolution of the unit cell volume of the solid solution with 12% of Fe{sup 2+} can be described by a third-order Birch-Murnaghan equation of state with parameters V{sub 0} = 281.0(5) {angstrom}{sup 3}, K{sub 0} = 102.8(3) GPa, K{prime}{sub 0} = 5.44. The spin pairing of the Fe{sup 2+} d-electrons occurs between 49 and 52 GPa, as evidenced by a discontinuous volume change. The transition pressure is increased by about 5 GPa compared with the iron end-member; an effect consistent with a cooperative contribution of adjacent clusters to the spin transition. The trend is, however, opposite in the periclase-wustite solid solution. Differences among the two structures, in particular in the Fe-Fe interactions, that might explain the different behavior are discussed.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1002810
- Journal Information:
- High Pressure Res., Journal Name: High Pressure Res. Journal Issue: (2) ; 06, 2010 Vol. 30; ISSN 0895-7959; ISSN HPRSEL
- Country of Publication:
- United States
- Language:
- ENGLISH
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