Highlights

Magnetic Charge Crystallization in Artificial Spin Ice

Chris Leighton (IRG-3), in collaboration with the Univ. of Illinois, Penn State, and Los Alamos

“Artificial spin ice” is a term used for arrays of nanoscale magnetic islands on lattices that geometrically frustrate inter-island interactions.

(Wheeler et al., Nat. Commun.,4, 2197, 2013)

Jan 22, 2014

University of Minnesota - Twin Cities

Ligand-free Colloids and Surface Doping of Silicon Nanocrystals

Uwe Kortshagen

Inks of inorganic nanocrystals hold great promise for printed electronics but the widely used organic surfactants (ligands) needed to stabilize these inks degrade the electrical quality of the printed films.

(a) The non-local resistance anomaly observed in Fe/Cu spin valves (red points), in which the polarization of the current decreases with decreasing temperature. The effect does not occur in Fe/Al (blue)or in Fe/Cu devices with Al interlayers. (b) The effect is due to the formation of a screening cloud around local moments (the Kondo effect). The effect saturates at low temperature, but the polarization of the current is reduced below its ideal value.

Jan 22, 2014

University of Minnesota - Twin Cities

Kondo Physics at Ferromagnet/Normal Metal Interfaces

P. A. Crowell and C. Leighton

The idealized picture of an interface between two elemental materials is simply an abrupt transition between planes containing two different types of atoms.

Jan 19, 2014

Northwestern University

Enhanced Refractive Index Sensing with Monodisperse Faceted Plasmonic Nanoparticles

Yu Jin Shin, Emilie Ringe, Michelle L. Personick, M. Fernanda Cardinal, Chad A. Mirkin, Laurence D. Marks, Richard P. Van Duyne, and Mark C. Hersam

The shape-dependent optical properties of metal nanostructures have motivated efforts to correlate nanoparticle structure with plasmonic behavior. In particular, gold bipyramids (BPs) are of interest due to their sharp tips that lead to strong localized field enhancement and high sensitivity to the surrounding environment. However, despite their potential, relatively few reports have studied the optical properties of sub-100 nm BPs due to their relatively low synthetic yields. To overcome this issue, density

Jan 19, 2014

Northwestern University

Northwestern MRSEC Partnerships Nucleate New Centers

Northwestern MRSEC provides the physical and intellectual infrastructure to nucleate collaborative opportunities in materials research both on and off the Northwestern campus, and continues to leverage its diverse portfolio of research into new educational and commercial opportunities. Recent examples include:

Dec 5, 2013

University of Utah

Utah MRSEC Teaching the Teachers

Debra Mascaro, Utah MRSEC, University of Utah Mechanical Engineering.

Teaching the Teachers Electromagnetism at the Physical Sciences Inquiry Academy These fifth-grade teachers are building electromagnetic ping pong ball launchers to demonstrate electromagnetism to their students. Utah MRSEC leads lessons and activities for teachers, as well as provides educational kits which supplement curriculum andcoordinate with Utah Core Standards. Participants:

Dec 5, 2013

University of Utah

Graphene-Insulator-Graphene Active THz Devices

Berardi Sensale-Rodriguez, Department of Electrical and Computer Engineering, The University of Utah, Salt Lake City, Utah 84112, USA

Discovery: Graphene-based plasmonic structures composed of graphene-insulator-graphene can provide gain at THz frequencies due to interplay between plasmons and resonant-tunneling.

Oct 21, 2013

University of Pennsylvania

Protein 'Passport' That Help Nanoparticles Get Past Immune System

Paul A. Janmey and Dennis E. Discher

What’s the Problem? Macrophages are part of the innate immune system and will try to eat anything they don’t recognize as being part of the body — they’re like border patrol guards, checking everybody’s passports. If you’re a red blood cell, you have the right passport and get waved on. But if you’re a piece of dirt or a bacterium, you don’t have the right passport, and Macrophages get you. The problem is that there are some things we actually want to be in body, like drug-delivery particles, that get eaten by these

Oct 10, 2013

University of Wisconsin - Madison

Monolayers of Organic Semiconductors with High Hole Mobility

E. Mannebach, J. W. Spalenka, P. S. Johnson, Z. Cai, F. J. Himpsel, and P. G. Evans

The electronic properties of thin films with thicknesses of only a single molecular layer have in the past typically been far worse than thicker films of the same material.

Oct 9, 2013