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The development of stress in the SrBi2Ta2O9 (SBT) films generated from a chemical solution deposition method was monitored during processing using wafer curvature measurements. Stress measurements of the entire Si/SiO2/Pt/SBT stack revealed an overall tensile stress of ∼536 MPa. The greatest increase in tensile stress was recorded for the anneal of the Pt bottom electrode and was due to the thermal expansion mismatch. Deposition of an amorphous SBT layer on the Pt, followed by a low temperature anneal (300°C), had little overall effect on the stress of the stack; however, upon crystallization, significantly more tensile stress was introduced into the stack. To further investigate the effect that stress has on the various electrical properties SBT films, wafers with different stress states were produced and SBT films deposited on them. Initial investigations indicate that SBT films on wafers with a higher tensile stress displayed improved ferroelectric hysteresis and switchable polarization.

The spatial distribution and atomic mobility of Li ions in the solid solution system Li1-xNb1-xWxO3 (0 ≤ x ≤ 0.5) have been studied using solid-state NMR techniques. To maintain charge balance, for each tungsten atom substituting on a niobium site, a lithium vacancy is produced in the lithium sublattice. 6Li magic angle spinning experiments reveal multiple lithium sites, attributed to distributions of niobium and tungsten neighbors. Dipolar 7Li second moments measured at low temperature (−100 °C) depend linearly on lithium content, consistent with a random distribution of vacancies. Variable temperature (−20 to 550 °C) 7Li NMR studies as a function of composition give evidence for two distinct motional processes: at low temperatures (near 0 °C) a local hopping process involving only a minority of the lithium ions present is activated. At high temperatures (300 °C and above, depending on substitution levels) long-range diffusion involving all the lithium atoms is evident on the NMR time scale. As the subs...

This paper reports on infrared spectroscopy that was used to monitor and characterize solutions used in the preparation of PZT 53/47 powders, dried gels, and thin layers deposited on platinized silicon substrates. It was found that careful control of the chemistry of the precursor solutions, in particular the control of the formation of esters and their elimination, resulted in reproducible solutions which could be used to prepare thin layers with superior properties. In addition, it was found that phase development and microstructure were related to the precursor chemistry. Single-phase perovskite layers with uniform microstructures resulted from ester-free solutions and were suitable for ferroelectric applications (P[sub r] [approximately] 22 [mu]C/cm[sup 2], E[sub c] [approximately] 80 kV/cm, K [approximately] 800, tan [delta] [approximately] 0.01).

The global market for wireless sensor networks in 2010 will be valued close to $10 B, or 200 M units. TPL, Inc. is a small Albuquerque based business that has positioned itself to be a leader in providing uninterruptible power supplies in this growing market with projected revenues expected to exceed $26 M in 5 years. This project focused on improving TPL, Inc.'s patent-pending EnerPak{trademark} device which converts small amounts of energy from the environment (e.g., vibrations, light or temperature differences) into electrical energy that can be used to charge small energy storage devices. A critical component of the EnerPak{trademark} is the supercapacitor that handles high power delivery for wireless communications; however, optimization and miniaturization of this critical component is required. This proposal aimed to produce prototype microsupercapacitors through the integration of novel materials and fabrication processes developed at New Mexico Technology Research Collaborative (NMTRC) member institutions. In particular, we focused on developing novel ruthenium oxide nanomaterials and placed them into carbon supports to significantly increase the energy density of the supercapacitor. These improvements were expected to reduce maintenance costs and expand the utility of the TPL, Inc.'s device, enabling New Mexico to become the leader in the growing global more » wireless power supply market. By dominating this niche, new customers were expected to be attracted to TPL, Inc. yielding new technical opportunities and increased job opportunities for New Mexico. « less

Organic polymeric materials, often used as ceramic processing aids to assist in the fabrication of green bodies, are thought to be of a temporary nature, being easily removed by thermolysis at temperatures between 250{degrees} and 600{degrees}C. This paper reports the interaction of various poly(vinyl butyral) binders with fine, high-purity alumina powder investigated using variable-temperature Fourier-transform infrared spectroscopy and thermal gravimetric analysis. It was found that there was interaction between the functionality of the polymers and the surface of the alumina powders. If these interactions are strong enough to persist to initial sintering temperatures, the polymers would not then be merely innocuous temporary processing aids, but could have an effect on the development of ceramic microstructures.