Effect of restricted geometry and external pressure on the phase transitions in ammonium hydrogen sulfate confined in a nanoporous glass matrix
A study of heat capacity, thermal dilatation, susceptibility to hydrostatic pressure, permittivity and polarization loops was carried out on NH4HSO4–porous glass nanocomposites (AHS + PG) as well as empty glass matrices. The formation of dendrite clusters of AHS with a size, dcryst, exceeding the pore size was found. An insignificant anisotropy of thermal expansion of AHS + PG showing statistically uniform distribution of AHS with random orientations of nanocrystallites over the matrix was observed. The effect of internal and external pressures on thermal properties and permittivity was studied. At the phase transition P-1 ↔ Pc, a strongly nonlinear decrease in the entropy ΔS2 and volume strain (ΔV/V)T2 was observed with decreasing dcryst. The linear change in temperatures of both phase transitions P-1 ↔ Pc ↔ P21/c under hydrostatic pressure is accompanied by the expansion of the temperature range of existence of the ferroelectric phase Pc, while this interval narrows as dcryst decreases.
The reported study was funded by Russian Foundation for Basic Research (RFBR) according to the Research Project No. 16-32-00092 mol_a.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
- 2.Kumzerov Y, Vakhrushev S (2007) Nanostructures within porous materials. In: Nalwa HS (ed) Encyclopedia of nanoscience and nanotechnology. American Scientific Publishers, New York, pp 1–39Google Scholar
- 3.Longo E, La Porta FA (eds) (2017) Recent advances in complex functional materials from design to application. Springer, BerlinGoogle Scholar
- 5.Deshmukh K, Ahamed MB, Sadasivuni KK, Ponnamma D, Deshmukh RR, Trimukhe AM, Pasha SSK, Polu AR, Al Maadeed MA-A, Chidambaram K (2017) Solution-processed white graphene-reinforced ferroelectric polymer nanocomposites with improved thermal conductivity and dielectric properties for electronic encapsulation. J Polym Res 24:27–31CrossRefGoogle Scholar
- 6.Komalavalli P, Banu I (2018) Enhanced room temperature multiferroic properties of nickel ferrite and lithium niobate nanocomposites. J Mater Sci: Mater Electron 29:3980–3984Google Scholar
- 14.Tarnavich V, Korotkov L, Karaeva O, Naberezhnov A, Rysiakiewicz-Pasek E (2010) Effect of restricted geometry on structural phase transitions in KH2PO4 and NH4H2PO4 crystals. Opt Appl 40:305–309Google Scholar
- 26.Flerov IN, Zinenko VI, Zherebtsova LI, Iskornev IM, Blat DCh (1975) Study of phase transitions in ammonium hydrosulfate. Izvestiya AN USSR (seriya fizicheskaya) 39:752–757Google Scholar
- 31.Bruker AXS TOPAS V4 (2008) General profile and structure analysis software for powder diffraction data—user’s manual. Bruker AXS, KarlsruheGoogle Scholar
- 32.Rysiakiewicz-Pasek E, Popravski R, Urbanowicz A, Maczka M (2005) Porous glasses with sodium nitrite impregnations. Opt Appl 35:769–774Google Scholar
- 35.Iskornev IM, Flerov IN (1978) Thermal expansion of ferroelectric crystals of the ammonium hydrosulfate family. Fizika Tverdogo Tela 20:2649–2653Google Scholar
- 36.Lines ME, Glass AM (1979) Principles and applications of ferroelectrics and related materials (international series of monographs on physics). Oxford University Press, OxfordGoogle Scholar
- 38.Polandov IN, Mylov VP, Strukov BA (1969) About p–T phase diagram of ferroelectric crystal NH4HSO4. Sov Phys Solid State 10:1754–1756Google Scholar