Phase transition and compressibility of LaF3 under pressures up to 40 GPa
2002; Elsevier BV; Volume: 335; Issue: 1-2 Linguagem: Inglês
10.1016/s0925-8388(01)01829-1
ISSN1873-4669
AutoresT. I. Dyuzheva, L. M. Lityagina, G. B. Demishev, N. A. Bendeliani,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoThe compressibility of LaF3 (tysonite) has been studied up to 40 GPa using X-ray diffraction in a diamond anvil cell. A phase transition from tysonite to an orthorhombic phase (Cmma, No. 67) was observed at a pressure of 19 GPa at room temperature. The volume discontinuity was ΔV/V0=−0.077 at the transition point. The cell parameters of the high-pressure phase are a=8.221(6) Å, b=8.589(9) Å, c=5.231(6) Å, Z=8 at p=16 GPa, which is accepted conventionally as equilibrium. The bulk moduli and pressure derivatives calculated by fitting V(p) data to the Birch–Murnagan equation of state are presented for both phases.
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