Structure and dielectric response of Na1 − x
                     K
                x
              NO2 nanocomposite solid solutions

Vakhrushev, S. B.; Golosovsky, I. V.; Koroleva, Ekaterina; Набережнов, А. А.; Okuneva, N. M.; Smirnov, A. B.; Фокин, А. В.; Tovar, M.; Glazman, M.

doi:10.1134/s1063783408080271

Cited by 10 publications

(6 citation statements)

References 13 publications

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“…All these new peculiarities found associated with expression (10) opens new possibilities in analysis of the dielectric function response that describes the behavior of the complex dielectric permittivity in wide frequency/temperature interval. Table 1 The values of the fitting parameters entering into the Arrhenius relationships (28) and (29).…”

Section: Discussionmentioning

confidence: 99%

“…For NCM on base of porous glasses the lowering of T C at decreasing average pores diameter was observed [26]. Unfortunately up-to-now the problem of correct analysis of dielectric spectra for NCM is open, because there are no theoretical calculations of effective dielectric permittivity of media with random (in contrast to from MCM and opals with regular 3D structure of channels) dendrite 3D net of nanochannels and the analysis of dielectric data was carried out using empirical approaches and functions [28,29].…”

Section: Experimentalsmentioning

confidence: 99%

See 1 more Smart Citation

The generalized Jonscher's relationship for conductivity and its confirmation for porous structures

Попов

Nigmatullin

Koroleva

et al. 2012

Journal of Non-Crystalline Solids

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Section: Discussionmentioning

confidence: 99%

Section: Experimentalsmentioning

confidence: 99%

The generalized Jonscher's relationship for conductivity and its confirmation for porous structures

Попов

Nigmatullin

Koroleva

et al. 2012

Journal of Non-Crystalline Solids

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“…Sodium nitrite can be easily embedded into different artificial and natural porous matrices, with various geometry, topology and connectivity of pores, due to its high wetting ability. The dielectric response of SN in opals and porous glasses was reported by several authors [4][5][6][7] and it has been shown that above T C an anomalous growth of the permittivity is observed and the permittivity ε reaches a value of the order of 10 8 at 100 Hz. More recently, similar growth of ε near T C has been observed in SN in mesoporous matrices MCM-41 and SBA-15 [8,9].…”

Section: Introductionmentioning

confidence: 73%

The negative phonon confinement effect in nanoscopic sodium nitrite

et al. 2009

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A nanocomposite of porous glass and a NaNO(2) ferroelectric (channels of approximately 7 nm diameter) was studied using infrared reflectivity, THz transmission and Raman spectroscopy as a function of temperature in the range of 300-500 K, including the ferroelectric transition. From the infrared and THz response the effective dielectric function was calculated and compared with the dielectric functions calculated from the Bruggeman and Lichtenecker models of the effective medium, using the known data on the polar phonon modes of the NaNO(2) single crystals. The results show good qualitative agreement, indicating that the stiffening of the effective modes is due to local depolarization fields on the glass-ferroelectric interfaces. The nonpolar Raman modes show no substantial modification compared to those of the bulk NaNO(2). Some signatures of the ferroelectric transition were even seen. The results indicate that the intrinsic size effect (phonon confinement) is negligible in this nanocomposite.

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“…We have performed the preliminary neutron diffraction measurements of the temperature evolution of PG7CKNO 3 crystal structure and have determined the KNO 3 nanoparticle size. It was 20 (2) nm for both types of samples, i.e., in PG7 potassium nitrate forms a dendrite structure occupying some neighboring pores as in the case of some other dielectrics: NaNO 2 , [14,15] KD 2 PO 4 [16] NaNO 3 . [17] As for the crystal structure of the 'virgin' PG7CKNO 3 sample prepared from melt, it corresponds to the coexistence of ferroelectric phase and a small amount of low-temperature paraelectric phase (Figure 3).…”

Section: Neutron Diffraction Datamentioning

confidence: 99%

Phase transitions in nanostructured potassium nitrate

et al. 2014

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Dielectric properties and temperature evolution of the crystal structure of nanocomposites on the basis of porous glasses and KNO 3 embedded into the pores have been studied on heating and cooling. It is shown that the stability of the ferroelectric phase depends on nanoparticle sizes and temperature prehistory of sample preparation and measurement procedure. The temperature interval, where the ferroelectric phase exists, increases on decreasing of the nanoparticle size. In the composite of KNO 3 and porous glasses with the average pore diameters of 7 nm, the ferroelectric phase becomes stable down to 100 K after the first heatingÀcooling circle. IntroductionAt room temperature (RT) the bulk potassium nitrate (KNO 3 ) has the orthorhombic structure Pmnc (a-phase or phase II). At 403 K a reconstructive phase transition (PT) from the low-temperature paraelectric phase to the high-temperature paraelectric trigonal phase R 3 m (b-phase, phase I) occurs. On cooling from this b-phase KNO 3 transforms to another trigonal phase R 3 m (g-phase) at the temperature »397 K. This g-phase is ferroelectric and remains stable on cooling down to 378 K and below this temperature a transformation into the initial a-phase takes place. For thin films and ultradispersed particles, the situation changes essentially. For example, in paper [1] it has been shown that KNO 3 thin films exhibit ferroelectric properties at temperatures even below 273 K possibly due to different thermal expansion of film and substrate. Later on, similar changes in the g ! a PT temperature have been observed for KNO 3 powders and it was attributed to cooperative behavior. [2] It has been demonstrated [3] that thin films have address voltages between 2 and 6 V, depending on the thickness, switching times as fast as 20 ns and square hysteresis loops. It opens a possibility to use KNO 3 thin films as materials for production of non-volatile ferroelectric random access memory (FeRAM). [4] As for nanocomposite materials (NCMs) with KNO 3 , the studies [5À9] carried out for NCM on the basis of mesoporous molecular sieves MCM-41,[10] having an ordered

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Structure and dielectric response of Na1 − x K x NO2 nanocomposite solid solutions

Cited by 10 publications

References 13 publications

The generalized Jonscher's relationship for conductivity and its confirmation for porous structures

The generalized Jonscher's relationship for conductivity and its confirmation for porous structures

The negative phonon confinement effect in nanoscopic sodium nitrite

Phase transitions in nanostructured potassium nitrate

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