Brian Foley’s paper, “Glass-like thermal conductivity of (010)-textured lanthanum-doped strontium niobate synthesized with wet chemical deposition,” has been published in the Journal of the American Ceramic Society (DOI: 10.1111/jace.13318). In this work, we have demonstrated that solution-based chemistry can produce highly textured, single crystalline oxide-films of strontium niobate with ultra-low thermal conductivities. the low thermal conductivities originate due to the variable and layered bonding environments in this perovskite structure. Congrats Brian!!!
Abstract
We have measured the cross-plane thermal conductivity (κ) of (010)-textured, undoped, and lanthanum-doped strontium niobate (Sr2−xLaxNb2O7−δ) thin films via time-domain thermoreflectance. The thin films were deposited on (001)-oriented SrTiO3 substrates via the highly-scalable technique of chemical solution deposition. We find that both film thickness and lanthanum doping have little effect on κ, suggesting that there is a more dominant phonon scattering mechanism present in the system; namely the weak interlayer-bonding along theb-axis in the Sr2Nb2O7 parent structure. Furthermore, we compare our experimental results with two variations of the minimum-limit model for κ and discuss the nature of transport in material systems with weakly-bonded layers. The low cross-plane κ of these scalably-fabricated films is comparable to that of similarly layered niobate structures grown epitaxially.
B.M.F. is grateful for support from the ARCS Foundation Metro Washington Chapter. P.E.H. is appreciative for funding through the Army Research Office (W911NF-13-1-0378) and the NSF EAGER program (CBET-1339436). This work was performed in part at the Center for Atomic, Molecular, and Optical Science (CAMOS) at the University of Virginia. This work was supported, in part, by the Laboratory Directed Research and Development (LDRD) pro- gram at Sandia National Laboratories (H.B-S., M.J.C., D.L.M., P.G.C, J.F.I., P.E.H.). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. This project was supported by Financial Assistance Award No. 01-79-14214, awarded by U.S. Department of Commerce Economic Development Adminis- tration, to the University of Virginia (P.E.H, B.M.F). The content is solely the responsibility of the authors and does not necessarily represent the official views of the U.S. Department of Commerce Economic Development Administration.
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