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Surface Functionalized Barium Titanate Nanoparticles: A Combined Experimental and Computational Study

ECS Journal of Solid State Science and Technology

Domrzalski, Jessica N.; Stevens, Tyler E.; Van Ginhoven, Renee M.; Fritzsching, Keith F.; Walder, Brennan W.; Johnson, Emily M.; Lewis, Riley E.; Vreeland, Erika C.; Pearce, Charles J.; Vargas, David A.; Coker, Eric N.; Laros, James H.; Grey, John K.; Monson, Todd M.

Barium titanate (BTO) nanoparticles show great potential for use in electrostatic capacitors with high energy density. This includes both polymer composite and sintered capacitors. However, questions about the nanoparticles’ size distribution, amount of agglomeration, and surface ligand effect on performance properties remain. Reducing particle agglomeration is a crucial step to understanding the properties of nanoscale particles, as agglomeration has significant effects on the composite dielectric constant. BTO surface functionalization using phosphonic acids is known reduce BTO nanoparticle agglomeration. We explore solution synthesized 10 nm BTO particles with tert-butylphosphonic acid ligands. Recent methods to quantifying agglomeration using an epoxy matrix before imaging shows that tert-butylphosphonic acid ligands reduce BTO agglomeration by 33%. Thermometric, spectroscopic, and computational methods provide confirmation of ligand binding and provide evidence of multiple ligand binding modes on the BTO particle surface.

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Soft Magnetic Multilayered FeSiCrB-Fe x N Metallic Glass Composites Fabricated by Spark Plasma Sintering

IEEE Magnetics Letters

Monson, Todd M.; Zheng, Baolong; Delany, Robert E.; Pearce, Charles J.; Langlois, Eric L.; Lepkowski, Stefan M.; Stevens, Tyler E.; Zhou, Yizhang; Atcitty, Christopher B.; Lavernia, Enrique J.

Novel multilayered FeSiCrB-Fe x N (x = 2-4) metallic glass composites were fabricated using spark plasma sintering of FeSiCrB amorphous ribbons (Metglas 2605SA3 alloy) and Fe x N (x = 2-4) powder. Crystalline Fe x N can serve as a high magnetic moment, high electrical resistance binder, and lamination material in the consolidation of amorphous and nanocrystalline ribbons, mitigating eddy currents while boosting magnetic performance and stacking factor in both wound and stacked soft magnetic cores. Stacking factors of nearly 100% can be achieved in an amorphous ribbon/iron nitride composite. FeSiCrB-Fe x N multilayered metallic glass composites prepared by spark plasma sintering have the potential to serve as a next-generation soft magnetic material in power electronics and electrical machines.

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Unprecedented magnetic behaviour in lanthanide-based ionic liquids

Chemical Communications

Monson, Todd M.; Stevens, Tyler E.; Leger, Jean L.; Manson, Jamie L.; Lovejoy, Katherine S.; Newsham, Aimee L.; Del Sesto, Rico E.

Ionic liquids containing lanthanide halide anions give the opportunity to investigate magnetic behaviour in non-ordered systems. Reported herein is the synthesis and characterization of ionic liquids containing a series of lanthanide halide anions, with the resulting materials displaying unusual behaviour below 50 K. Specifically, the ionic liquid structural glass formation appears to drive magnetic behaviour due to cluster formation of the anions during rapid cooling. This system presents a possible probe to study the dynamics of glass forming materials.

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Results 1–25 of 32
Results 1–25 of 32