Pressure-induced staging transitions and stage disorder in dilute potassium-graphite intercalation compounds

Journal Article · Fri May 01 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.6826· OSTI ID:5975130

Fischer, J E; Kim, H J

We extend our previous study of high-pressure staging transitions and stage disorder to dilute potassium-graphite intercalation compounds, using the Hendricks-Teller analysis of elastic neutron scattering (00L) profiles measured at 300 K over a broad q range. The dilute regime begins at a concentration (K)/(C)approx. <1/33, all samples in this regime behaving qualitatively the same at high pressure. A continuous transition starts immediately near P = 0, leading to a well-ordered higher stage with no apparent connection to in-plane density or structure. This is stable only over a small range, transforming abruptly at slightly higher P to a still higher stage or stage mixture, the index of which is consistent with the specific in-plane density imposed by commensurate 2 x 2 lockin. Disorder generally increases with average stage index (i.e., with increasing P or decreasing (K)/(C) ratio), consistent with the theory of Kirczenow. Disorder in the most dilute samples is better represented by a skewed distribution of many stage packages than by a random mixture of two or three different stage cells.

• Research Organization: Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, Pennsylvania 19104
• OSTI ID: 5975130
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:13; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602 -- Other Materials-- Structure &amp; Phase Studies
654003* -- Radiation &amp; Shielding Physics-- Neutron Interactions with Matter
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METALS
CARBON
CLATHRATES
COHERENT SCATTERING
CRYSTAL-PHASE TRANSFORMATIONS
DATA
DIFFRACTION
ELASTIC SCATTERING
ELEMENTAL MINERALS
ELEMENTS
EXPERIMENTAL DATA
GRAPHITE
INFORMATION
MEDIUM TEMPERATURE
METALS
MINERALS
NEUTRON DIFFRACTION
NONMETALS
NUMERICAL DATA
ORDER-DISORDER TRANSFORMATIONS
PHASE TRANSFORMATIONS
POTASSIUM
PRESSURE DEPENDENCE
SCATTERING