TY  - JOUR
AU  - Mishra, S. K.
AU  - Mittal, R.
AU  - Chaplot, S. L.
AU  - Ovsyannikov, S. V.
AU  - Trots, D. M.
AU  - Dubrovinsky, L.
AU  - Su, Y.
AU  - Matsuishi, S.
AU  - Hosono, H.
AU  - Garbarino, G.
AU  - Brückel, Thomas
TI  - Pressure-driven Phase Transition in CaFeAsF at 40 and 300 K
JO  - Journal of physics / Conference Series
VL  - 377
SN  - 1742-6596
CY  - Bristol
PB  - IOP Publ.
M1  - FZJ-2017-06675
SP  - 012034 -
PY  - 2012
AB  - We carried out systematic investigation of high pressure crystal structure and structural phase transition upto 46 GPa at 40 K and 25 GPa at 300 K in CaFeAsF using powder synchrotron x-ray diffraction experiments. Rietveld analysis of the diffraction data at 40 K reveals a structural phase transition from an orthorhombic to a monoclinic phase at Pc = 13.7 GPa, while increasing pressure. The transition to a lower symmetry phase (orthorhombic to monoclinic) in this 1111 compound under pressure is in contrast with the transition to a high symmetry phase (orthorhombic to tetragonal) as observed in the '122' type compounds. On heating from 40 K at high pressure, CaFeAsF undergoes a monoclinic to tetragonal phase transition around 25 GPa and 200 K. Further, it does not show any post-tetragonal phase transition, as observed in '122' compounds (CaFe2As2, BaFe2As2), and remains in the tetragonal phase upto 25 GPa at 300 K. The dPc/dT slope is found to be positive for CaFeAsF and CaFe2As2, unlike a negative gradient was found in case of BaFe2As2.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000307728500034
DO  - DOI:10.1088/1742-6596/377/1/012034
UR  - https://juser.fz-juelich.de/record/837905
ER  -