TY - JOUR
T1 - Movers, shakers, and storers of charge
T2 - The legacy of ferroelectricians L. Eric Cross and Robert E. Newnham
AU - Trolier-McKinstry, Susan
AU - Randall, Clive A.
N1 - Funding Information:
In the mid-1990's, numerous synthesis routes to fabricate complex crystal particles at ~10 nm length scale were published. Cross and Newnham, noting that this would be important for the future of ferroelectric materials and applications, won research programs from a variety of sources including the National Science Foundation, the Department of Defense and the Defense Advanced Research Projects Agency to explore these opportunities. There were also the challenges of understanding surface properties over bulk, and separating the size effect phenomena in the ferroelectric materials, and the ability to characterize properties and structure at this length scale. A further challenge was processing high quality materials to produce dense ceramics and/or composites without compromising the nanometer length scale; this is challenging with sintering and the competition of densification and grain growth. These studies provided further insight into size effects of ferroelectrics. Through use of BaTiO3-based glass ceramics, they were able to demonstrate that for an adequately insulating matrix phase, BaTiO3 grains remain usefully ferroelectric to a critical size of 17 nm. Below this size, depolarization fields limit the stability of the ferroelectric phase. Through mixing law analysis, the scaling effects on the phase transition behavior were characterized, including the shift in transition temperatures, magnitude of permittivity, and breath of phase transition. Another challenge was the control of connectivity for nanosize ferroelectric particles. It was found that new directed assembly techniques such as dielectrophoresis in polymers could enhance properties by aligning nanoparticles under conditions of in-situ polymerization in thermosetting polymers. Since those early days many new processing techniques and assembly methods have evolved, but that early work outlined many of the important size effects and approaches that need to be taken in nanosized bulk ferroelectrics. As mentioned above, tons of nanosized BaTiO3 powders are being used to manufacture the state of the art capacitors that are ubiquitous to modern electronic systems.
Publisher Copyright:
© 2017 The American Ceramic Society
PY - 2017/8
Y1 - 2017/8
N2 - The last 100 years has seen the burgeoning of the field of ferroelectrics from a scientific curiosity to the basis of major industries in capacitors, piezoelectrics, and electro-optics. This paper will discuss the history of the field, with an emphasis on the contributions made by Professors Robert E. Newnham and L. Eric Cross of the Pennsylvania State University. Their scientific contributions encompassed many key areas in ferroelectrics, including phenomenology, structure determination, relaxor ferroelectrics, composite piezoelectrics, structure-property relations, and flexoelectricity. Scientific advances were often motivated by and closely coupled with application needs. Finally, their impact on global academic communities is discussed.
AB - The last 100 years has seen the burgeoning of the field of ferroelectrics from a scientific curiosity to the basis of major industries in capacitors, piezoelectrics, and electro-optics. This paper will discuss the history of the field, with an emphasis on the contributions made by Professors Robert E. Newnham and L. Eric Cross of the Pennsylvania State University. Their scientific contributions encompassed many key areas in ferroelectrics, including phenomenology, structure determination, relaxor ferroelectrics, composite piezoelectrics, structure-property relations, and flexoelectricity. Scientific advances were often motivated by and closely coupled with application needs. Finally, their impact on global academic communities is discussed.
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U2 - 10.1111/jace.15021
DO - 10.1111/jace.15021
M3 - Article
AN - SCOPUS:85021774100
SN - 0002-7820
VL - 100
SP - 3346
EP - 3359
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 8
ER -