The low-temperature behaviour of the pyroelectric coefficient

Gavrilova, N. D.; Maksimov, Eugene G.; Novik, V. K.; Drozhdin, S. N.

doi:10.1080/00150198908007918

Cited by 18 publications

(7 citation statements)

References 22 publications

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“…Subsequent investigations support these observations and show that tourmaline pyroelectric coefficients (P'3)range between -1.8 and 5.4~C/(m2. K) at 296 K (Hayashi, 1912;Rontgen, 1914;Ackermann, 1915;Gladkii and Zheludev, 1965;Gavrilova, 1965;Fabel and Henish, 1971;Drozhdin et aI., 1975;Gavrilova et al 1989; the present work). Related studies have shown that piezoelectricity, the inducement of an electric charge by an applied stress, is also stronger in translucent colored tourmalines than in certain opaque black varieties (Cady, 1946).…”

Section: Introductionmentioning

confidence: 54%

Influence of chemistry on the pyroelectric effect in tourmaline

Hawkins

Mackinnon

Schneeberger

1995

American Mineralogist

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Pyroelectric coefficients were measured from a series of natural tourmaline crystals between -170 and -500 K to quantify the variation of the pyroelectric effect with chemical composition. The amount of Fe in tourmaline has a prominent influence on the pyroelectricity. Fe content linearly decreases the pyroelectric coefficient in the composition range between 0.01(1) and 14.6(2) wt% FeO. Thus, to a first approximation, tourmaline pyroelectric coefficients may be predicted directly from the chemical composition derived by routine electron probe microanalysis.The relationships between pyroelectricity and chemistry indicate that the pyroelectric coefficient is influenced to different extents by the occupancies of the X, Y, and Z cation sites in the tourmaline structure. The octahedral Y site occupancy strongly influences the pyroelectric coefficient due to the preference of Fe for this site. This work further suggests that the addition of Fe and Mg cations to the smaller Z octahedral site causes the pyroelectric coefficient to increase. However, because an extended suite of samples is not available in which the Z site contains ions other than AI, this proposed trend has not been experimentally determined. The chemistry of the ninefold coordinated X site and the population of this site do not influence the pyroelectric coefficients of tourmaline.

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Section: Introductionmentioning

confidence: 54%

Influence of chemistry on the pyroelectric effect in tourmaline

Hawkins

Mackinnon

Schneeberger

1995

American Mineralogist

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“…Tourmaline pyroelectric coefficients are found to range between 1.8 and 5.4 μC/(m 2 •K). 22,23 Electric fields on the order of 10 6 −10 7 V/m exist on the surface of micrometer-sized tourmaline. 21 The work presented here focuses on enhancing the quantum efficiency, that is, the Modification of MWNTs and TPs.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The intensity of electrical polarity is different for differently colored tourmalines, which is the result of the differences in composition. Tourmaline pyroelectric coefficients are found to range between 1.8 and 5.4 μC/(m 2 ·K). , Electric fields on the order of 10 6 –10 7 V/m exist on the surface of micrometer-sized tourmaline . The work presented here focuses on enhancing the quantum efficiency, that is, the electron transition between CNTs by integrating CNTs with the TPs having spontaneous surface electric fields into a polyurethane (PU) matrix by in situ polymerization.…”

Section: Introductionmentioning

confidence: 99%

Incorporating Strong Polarity Minerals of Tourmaline with Carbon Nanotubes to Improve the Electrical and Electromagnetic Interference Shielding Properties

Wang

Zheng

et al. 2012

J. Phys. Chem. C

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This paper describes a method for enhancing the electron transition among carbon nanotubes (CNTs) by integrating CNTs with a polar mineral tourmaline having spontaneous electric fields for conductive polymer composites. The thin polymer layer at the surfaces of CNTs raises the potential barrier of electron transition among CNTs, limiting the electrical properties. The incorporation of tourmaline particles (TPs) enhanced significantly the electrical properties of polyurethane/multiwalled carbon nanotube (PU/MWNT) composites. The electric fields of TPs lower the potential barrier by an applied external electric field. It is proposed that the enhanced electrical properties are due to a reduction in the potential barrier of electron hopping among CNTs. The results have important implications for enhancing the electrical properties of conductive polymer composites, endowing the composites with new fuctions, such as nagetive air ions and far-infrared emission. ■ INTRODUCTIONSince the discovery of carbon nanotubes (CNTs) in 1991 by Iijima, 1 they have received much attention for their many potential applications such as nanoelectronic and photovoltaic devices, 2,3 electrochemical capacitors, 4 nanowires, 5 electromagnetic interference (EMI) shielding materials, 6,7 and nanocomposite materials. 8,9 CNTs are regarded as ideal conductive fillers for preparing the conductive composites due to their very high aspect ratio and extraordinary electrical, mechanical, chemical, and electromechanical properties. 10−12 Nevertheless, major problems are the weak interfacial interaction between CNTs and a polymer as well as the difficulty in dispersion of CNTs in a polymer matrix due to its strong van der Waals interactions. 13,14 The chemical modification of CNTs is one of the most important approaches to overcome these problems. 15,16 Another way to improve conductivity in a polymer composite is to introduce secondary fillers, such as clay and CaCO 3 , into a polymer composite containing carbon black, 17 multiwalled carbon nanotubes (MWNTs), 18 single-walled carbon nanotubes (SWNTs) 19 as the conductive filler. The role of clay was to assist dispersion of the conductive fillers and thus result in better electrical proprieties. 19,20 To quantitatively evaluate the effect of electrically inert particulate fillers, the concept of effective concentration of MWNTs is proposed. 18 However, studies of the effect of strong polarity mineral particles such as tourmaline particles (TPs) on electrical properties of CNTs have not been published. Tourmaline is a natural silicate mineral exhibiting both pyroelectric and piezoelectric properties with a typical chemical formula of XY 3 Z 6 (T 6 O 18 )(BO 3 ) 3 V 3 W, where X = Na + , Ca 2+ , K + , or vacancy Y = Li + , Fe 2+ , Mg 2+ , Fe 3+ , Al 3+ , Cr 3+ , V 3+ , (Ti 4+ ) Z = Al 3+ , Fe 3+ , Mg 2+ , Cr 3+ , V 3+ , (Fe 2+ ) T = Si 4+ , Al 3+ , (B 3+ ) B = B 3+ or vacancy V = [O(3)] = OH − , O 2− W = [O(1)] = OH − , O 2− , F − and metal ions in parentheses indicate minor or possible substitution. 21...

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“…To answer this question would require systematic structural studies at varying temperature. A similar behaviour of polarization has been observed in Li 2 SeO 4 H 2 O [11,12] where at 100 K the dipole moment of the unit cell was reversed as a result of temperature dependent rotation of water molecules [13].…”

Section: Results and Conclusionmentioning

confidence: 57%

Structure and Properties of [(CH₂OH)₃CNH₃]H₂AsO₄

Waśkowska

Dacko

Czapla

2003

Zeitschrift Für Naturforschung A

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Crystals of [(CH 2 OH) 3 CNH 3 ]H 2 AsO 4 have been grown, and X-ray diffraction analysis has shown them to be monoclinic, with space group P2 1 . A three-dimensional network of hydrogen bonds of the type O-H. . . O and N-H. . . O forms strong cation-cation and cation-anion linkages. Stabilizing the structure, they create favourable conditions in the crystal to be polar. The temperature dependent behaviour of the dielectric permittivity, measured along three crystal axes in the range 100 -300 K, did not show any evidence for a phase transition, while the pyroelectric properties of the crystal confirmed the lack of a centre of symmetry.These polar features locate [(CH 2 OH) 3 CNH 3 ]H 2 AsO 4 among the materials applicable to electrooptics and for the second harmonic generation.

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The low-temperature behaviour of the pyroelectric coefficient

Cited by 18 publications

References 22 publications

Influence of chemistry on the pyroelectric effect in tourmaline

Influence of chemistry on the pyroelectric effect in tourmaline

Incorporating Strong Polarity Minerals of Tourmaline with Carbon Nanotubes to Improve the Electrical and Electromagnetic Interference Shielding Properties

Structure and Properties of [(CH₂OH)₃CNH₃]H₂AsO₄

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The low-temperature behaviour of the pyroelectric coefficient

Cited by 18 publications

References 22 publications

Influence of chemistry on the pyroelectric effect in tourmaline

Influence of chemistry on the pyroelectric effect in tourmaline

Incorporating Strong Polarity Minerals of Tourmaline with Carbon Nanotubes to Improve the Electrical and Electromagnetic Interference Shielding Properties

Structure and Properties of [(CH2OH)3CNH3]H2AsO4

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Structure and Properties of [(CH₂OH)₃CNH₃]H₂AsO₄