{"id":4885,"date":"2013-01-01T00:00:00","date_gmt":"2013-01-01T08:00:00","guid":{"rendered":"https:\/\/wpdev.hmc.edu\/physics\/2013\/01\/01\/measurement-of-bto-nanoparticle-permittivity-in-stable-dispersions\/"},"modified":"2013-01-01T00:00:00","modified_gmt":"2013-01-01T08:00:00","slug":"measurement-of-bto-nanoparticle-permittivity-in-stable-dispersions","status":"publish","type":"physics_clinic","link":"https:\/\/www.hmc.edu\/physics\/research\/clinic\/projects\/measurement-of-bto-nanoparticle-permittivity-in-stable-dispersions\/","title":{"rendered":"Measurement of BTO Nanoparticle Permittivity in Stable Dispersions"},"content":{"rendered":"<h2><span id=\"clinic-sponsor\">Sandia National Laboratories<\/span><br \/>\n<span id=\"clinic-year\">2013\u201314<\/span><\/h2>\n<p>Barium titanate (BTO) nanoparticles exhibit intriguing size-dependent structural and dielectric properties which make them a candidate for use in novel capacitor technologies. This year, Sandia National Laboratories has once again engaged a clinic team (SNL Ferroelectric 2013-14) at Harvey Mudd College to explore BTO nanoparticle behavior. Building upon last year\u2018s results, the current SNLFE clinic team has worked to finalize and implement a procedure for measuring the dielectric constant of BTO nanoparticles in stable dispersions by electrochemical impedance spectroscopy (EIS). We have investigated the effects of sonication on dispersion stability for a range of BTO\/solvent slurries, finding highly stable slurries of 50 nm Sakai KZM-50 series particles for low BTO loadings. Alternately, we successfully imbed BTO nanoparticles in an ULTEM polymer matrix at volume fractions up to 10%. In addition, we have measured the permittivity of 1 vol% to 10 vol% BTO slurries with high reproducibility (roughly 3% variation in permittivity between samples). However, our numerical models have revealed an extreme sensitivity of the calculated average particle permittivity to the measured overall dispersion permittivity.<\/p>\n<\/p>\n<p><p>We have also begun to probe the structure and ferroelectric behavior of BTO nanoparticles of different sizes and syntheses using a variety of spectroscopic, microscopic, and diffraction methods. For nanoparticles of 50 nm in diameter and smaller, preliminary atomic pair distribution function measurements confirm the absence of a sharp transition from tetragonal to cubic structure at the bulk Curie temperature. This lack of transition is in agreement with both the 2012-2013 and 2013-2014 Raman measurements, while in stark opposition to prior XRD measurements which indicate a cubic structure at all temperatures. These results suggest phase decoherence in smaller nanoparticles, which we speculate may be due to surface lattice distortions.<\/p>\n<p id=\"clinic-advisor\"><strong>Advisor(s):<\/strong> Richard Campbell Haskell and Adrian Hightower.<\/p>\n<p id=\"clinic-team\"><strong>Team:<\/strong> Robert G. Gambee &#8217;15, Sun Hwi Bang &#8217;14, Nathaniel (Nate) J. Bean &#8217;14, and Jean-Claude David de Sugny &#8217;14.<\/p>\n","protected":false},"author":1,"featured_media":0,"template":"","class_list":["post-4885","physics_clinic","type-physics_clinic","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_clinic\/4885","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_clinic"}],"about":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/types\/physics_clinic"}],"author":[{"embeddable":true,"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/users\/1"}],"wp:attachment":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/media?parent=4885"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}