High pressure phase transformation in MnS

Abstract

The structural, optical and electrical behaviour of MnS under high pressure was investigated. For X-ray investigations and optical observations a gasketed diamond anvil cell was used. Measurements of the electrical conductivity were performed in a Bridgmari opposed-anvil apparatus. A structural phase transition at 7.2 GPa from the cubic a-phase (NaC1-type) t o the B16-type structure (GeS-type) was detected by X-ray investigations and confirmed by optical observations. Measurements of the electrical conductivity showed a linear decreasing electrical gap energy in dependence on pressure.Es wurde das strukturelle, optische und elektrische Verhalten von MnS unter Druck untersucht. Fur die Rontgenuntersuchungen und die optische Beobachtung wurde eine gasketierte Diamantstempelkammer verwendet. Die Messung der elektrischen Leitfkhigkeit wurde in einer Bridgrnan-Flachstempelapparatur durchgefuhrt. Ein struktureller Phasenubergeng bei 7.2 GPa von der kubischen a-Phase (NaC1-Typ) in die B16-Struktur (GeS-Typ) wurde durch Rontgenuntersuchungen festgestellt und durch optische Beobachtungen bestiitigt. Die Messung der elektrischen Leitflihigkeit zeigte eine lineare Abnahme der elektrischen Gap-Energie in Abhiingigkeit vom Druck.

Compression of ?-MnS (alabandite) and a new high-pressure phase

“…Our result for the transition pressure from c~-MnS to HPP-MnS is consistent with Wakabayashi et al (1968) and McCammon (1991), but not with Kraft and Grueling (1988). We observed NaCl-type d-spacings (111,200,220, were observed at the Kraft and Grueling (1988) transition pressure of 7.2 GPa.…”

“…We observed NaCl-type d-spacings (111,200,220, were observed at the Kraft and Grueling (1988) transition pressure of 7.2 GPa. go'aft and Grueling (1988) also reported optical absorption and electrical resistivity changes for alabandite which they attributed to bandgap closure and a semiconductorto-metal transition.…”

“…No electrical resistivity measurements were done for the present study, however no metallic sheen was observed at any pressure. The results of Kraft and Grueling (1988) remain enigmatic. Discrepancies between their results and those of others could be explained by extraneous lattice diffractions from gasket material (suggested by McCammon 1991).…”

“…With a methanol-ethanol pressure medium, Kraft and Grueling (1988) found evidence for a structural phase transition at 7.2 GPa. At this pressure, they reported additional X-ray diffraction lines and the disappearance (9) 188.52 (5) 171.82 (7) 156.00 (6) --229.7 (5) 231.4 (5) 229.1 (5) 231.5 (12) 233.5 (2) 230.7 (3) 96.44 (3) 96.11 (2) 95.54 (2) 95.19 (3) 95.06 (4) Wakabayashi et al (1968) and Clendenen and Drickamer (1966), Ko and K' o were determined from an unweighted fit of'smoothed' data.…”

“…Working toward this goal, we have experimentally determined the equation-of-state and stability of e-MnS (alabandite) as a function of pressure. The high-pressure behavior of e-MnS was previously studied by Clendenen and Drickamer (1966), * Also affiliated with the James Franck Institute, University of Chicago Wakabayashi et al (1968), Kraft and Grueling (1988), and McCammon (1991), but their results were inconsistent.…”