Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures

Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures

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Datum:2010
1. Verfasser: Hofmeister, A.
Format: Artikel
Sprache:English
Veröffentlicht: Інститут геофізики ім. С.I. Субботіна НАН України 2010
Schriftenreihe:Геофизический журнал
Online Zugang:http://dspace.nbuv.gov.ua/handle/123456789/101391
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Zitieren:Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures / A. Hofmeister // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 57-58. — Бібліогр.: 7 назв. — англ.

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spelling irk-123456789-1013912016-06-04T03:01:54Z Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures Hofmeister, A. 2010 Article Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures / A. Hofmeister // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 57-58. — Бібліогр.: 7 назв. — англ. 0203-3100 http://dspace.nbuv.gov.ua/handle/123456789/101391 en Геофизический журнал Інститут геофізики ім. С.I. Субботіна НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
format Article
author Hofmeister, A.
spellingShingle Hofmeister, A.
Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
Геофизический журнал
author_facet Hofmeister, A.
author_sort Hofmeister, A.
title Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
title_short Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
title_full Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
title_fullStr Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
title_full_unstemmed Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
title_sort accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures
publisher Інститут геофізики ім. С.I. Субботіна НАН України
publishDate 2010
url http://dspace.nbuv.gov.ua/handle/123456789/101391
citation_txt Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures / A. Hofmeister // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 57-58. — Бібліогр.: 7 назв. — англ.
series Геофизический журнал
work_keys_str_mv AT hofmeistera accuratedeteriminationsofvibrationalandradiativethermaltransportinperovkiterocksaltandrelatedstructures
first_indexed 2025-07-07T10:52:04Z
last_indexed 2025-07-07T10:52:04Z
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fulltext ��������� ��� ���������������������� 04 ��� ��!"#�$%&'�("�%()�#*+#�' #(&"�&��&,#��-�%()� �)#..'(/ Accurate deteriminations of vibrational and radiative thermal transport in perovkite, rocksalt, and related structures A. Hofmeister, 2010 Department of Earth and Planetary Sciences, Washington University, Missouri, USA hofmeist@levee.wustl.edu That thermal diffusivity is connected with cooling front speed has gone unrecognized until recently [Hofmeister, 2010]. Consequently, ballistic radiative transport affecting virtually all measurements inten- ded to probe the vibrational mechanisms, even cryo- genic, has been overlooked [Hofmeister, 2010]. In addition, failure to correct for refraction, not simply reflection, effects has provided large systematic er- rors in estimating radiative thermal conductivity from spectra obtained in the diamond anvil cell for lower mantle phases. [Hofmeister, 2010; (in review)]. Re- cent discovery that thermal diffusivity (D) is linked to thermal expansivity ( ) [Hofmeister, (in review); Hofmeister, Whittington (in review)] coupled with overestimation of transport values for simple solids by acoustic models indicate that a much different theoretical approach wants consideration. To ad- dress these issues, to provide uncompromised va- lues of thermal transport properties, and a means to extrapolate such data to lower mantle conditions, various spectroscopic-based measurements on analogues have been conducted and a new model is under construction. We have recently measured the phonon compo- nent of thermal diffusivity (D) for lower mantle struc- tures from ambient temperature (T) up to ~2000 K using contact-free, laser-flash analysis, from which effects of ballistic radiative transfer were removed. We focused on 13 compounds (e. g., synthetic YAlO3:Tm, natural Ca1.01Mn0.001Fe0.007Ti0.99O3'�-��� .�/�0�1��������.�/0��1���*��1����/ � /��!�����2�� ��1�����������!���������-���3�����-4stites, and also studied a wide variety of glasses and upper mantel materials. Perovskites [Hofmeister, (in review)] in the absence of phase transitions) are best described as D 1 following a low order polynomial in T. Ordered, cubic perovskites occupy a single trend, defining the contribution of the ideal lattice. Distortion, disor- der, polymorphism, and temperature affect D 1 in a manner that is consistent with the damped harmonic oscillator-phonon gas model which relates phonon lifetimes to infrared peak widths. Combining our data with cryogenic measurements of YAlO3 and LaAlO3 [Agarwal et al., 2005] and similarly for fused silica [Agarwal et al., 2005] shows that the best descrip- tion for D 1(T) is a proportionality to T from ~0 K to the limit of measurements. At low T, D 1 ~T3, so acoustic modes dominate and klat = k0+k1T. Defects being present preclude scattering at sample walls, adding a small constant 1D0 ~0,0001 mm 2 s as T 0, and an additional contribution of kdfctT 3. Forms previously inferred for thermal insulators include sys- tematic errors stemming from ballistic radiative trans- fer and/or interface resistance, and misunderstand mechanisms. Our results show that optical phonons largely govern heat transport of complex insulators, including glasses. Alkali halides behave differently wherein interactions of optic and acoustic modes govern heat transfer up to melting [Yu, Hofmeister, (in prep.)]. Visible-UV spectra of Fe2+ and Fe charge transfer in single-crystal perovskite-types have overall mode- rate absorption coefficients and flat baselines, con- sistent with reflectivity data, confirming that DAC spec- tra are plagued by insufficient baseline corrections. We find that diffusive radiative thermal conductivity va- lues are similar to results obtained for olivines, permit- ing recasting of results to focus on iron concentrati- ons for a given site speciation (e.g., [Hofmeister, 2007]). Combining spectroscopic with direct heat trans- port measurements reveals microscopic mecha- nisms permitting extrapolation to the mantle. A de- tailed model with application to diverse materials will be presented in this talk. References Agarwal R. L., Riplin D. J., Ochoa J. R., Fan T. Y. Measurement of thermo-optic properties of Y3Al5O12, Lu3Al5O12, YAIO3, LiYF4, LiLuF4, BaY2F8, KGd(WO4)2, and KY(WO4)2 laser crystals in the 80—300 K tem- perature range // J. Appl. Phys. — 2005. — 98. — P.5103514. 05 ��������� ��� ���������������������� /#�)-(% '1%.�+,#(� #(%2 Hofmeister A. M. Thermal conductivity of Earth’s dee- pest Mantle // Superplume: Beyond Plate Tectonics / Eds. D. A. Yuen, S. Maruyama, S. I. Karato, B. F. Windley. — Dordrecht: Springer, 2007. — P. 269—292. Hofmeister A. M. Scale and directional errors in geo- physical models and measurements involving heat transport: Implications for global power and tem- peratures // Izvestia (in review). Hofmeister A. M. Scale aspects of heat transport in the diamond anvil cell, in spectroscopic modeling, and in Earth's mantle // Phys. Earth Planet. Inter. — 2010a. — 180. — P. 138—147. Hofmeister A. M. Thermal diffusivity of perovskite-type compounds at elevated temperature // J. Appl. Phys. — 2010b. — 107. — P.55103532. Hofmeister A. M., Whittington A. G. Effect of hydration and annealing on thermal diffusivity of fused quartz, fused silica, and their melts at high temperature from laser-flash analysis // J. Non-Crystalline Solids (in review). Yu X., Hofmeister A. M. Thermal diffusivity of alkali and silver halides // J. Appl. Phys. (in prep).

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