Giant magnetoresistance and kinetic phenomena in n-Ag4SSe in the vicinity of a phase transition

Probable metal–insulator transition in Ag4SSe

“…Fig. 8 [25], and very similar results, though not so well fitting to the straight lines, are reported in [21]. Thus, concluding the search for the analogy of our new low-temperature phase transition in Ag 4 SSe, we see that this finding is not alien to the Ag 2 S-Ag 2 Se system.…”

“…Besides, the same results were published in [35]. Other authors reported that the electrical conductivity r of Ag 4 SSe changes drastically near 290 K, with a-b transition at 348 K [21]. The explanations of experimental conditions in the paper were not quite correct, because the measurements are reported to be carried out in the temperature interval from 290 to 413 K, but the experimental points in Fig.…”

“…Thus, we may conclude that the transition point for our sample is 358.2 K, with negligible small hysteresis. This value is within the limits reported for Ag 4 SSe: 373 ± 5 [2], 367 ± 2 [20], and 348 K [21]. The transition enthalpy values are reproduced very well separately for heating (8.5, 8.5, 8.6 J g À1 ) and cooling (9.2, 9.1, 9.1 J g À1 ), but differ from one another by 7%.…”

“…For DSC, this point was clearly indicated in the title of report [3]. Other works were carried out with using derivatograph (MOM, Hungary) that operates only above room temperature [2,21,33]. X-ray diffraction is usually applied to the detection of phase homogeneity in the solid solutions under investigation, when only the unit cell parameters are of interest, without careful examination of extra weak reflections.…”

Sulfur–selenium isomorphous substitution and polymorphism in the Ag2(S,Se) series

“…The Ag 2 SAg 2 Se chalcogenides are characterized by the presence of phase transitions and structure phase transformations [1][2][3][4][5]. Roy et al [6] suggested using silver sulfide and selenide transitions as geologic thermometers.…”