Highlights

Novel magnetic behavior occurs when interactions between nanoscale phases dominate. In particular, interactions between hard and soft magnetic phases lead to dramatically improved energy densities. However, relevant interaction lengths make it necessary that the soft magnetic phase be on the order of 6-8 nanometers. Achieving this level of nanostructuring using conventional processing routes is virtually impossible. Here, we use a novel approach to generate phases with length scales never before achieved in granular systems.

Water soluble Gd-based endohedral metallofullerenes (Gd@C₈₂(OH)_x, Gd@C₆₀(OH)_x, and Gd@C₆₀[C(COOH)₁₀]) have been studied extensively as a result of their novel electronic and structural properties. These Gd-based metallofullerenes are regarded as a possible new generation of magnetic resonance imaging (MRI) contrast agents not only because of their excellent proton relaxivities but also because they may serve as a safer alternative.

Visiting school teachers, undergraduate students and their professors get a macroscale immersion in nanoscale research through summer programs at Materials Research Science and Engineering Center (MRSEC) at the University of Nebraska (NU). The Center fosters collaboration among NU physicists, chemists and engineers to advance nanomaterials research. Education and outreach is a vital part of the Center’s mission.

MRSEC researchers visited Clinton Elementary School to help students investigate the optical and electrical properties of solids. Twenty-three fourth-grade students did several different hands-on experiments involving electrical measurements, optical reflection and transmission, and observations of the refractive properties of transparent material. The students made and tested electrical circuits to study the conduction of various materials, including aluminum and glass.

Recent work in collaboration with scientists from National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan have demonstrated, both experimentally and theoretically, that O vacancies in the MgO barrier layer play a significant role in Fe/MgO/Fe(001) Magnetic Tunnel Junctions.

Recent work in collaboration with scientists at the International Center for Materials Physics, Chinese Academy of Sciences, Shenyang, has shown that multilayering a high-coercivity material based on Nd₂Fe₁₄B (NFB) with Fe can lead to ideal magnetic coupling. The figure shows the as-deposited multilayer structure with 16 nm of NFB (grey) and 6 nm of Fe (black/white). After heat treatment a fine scale two-phase nanocomposite granular structure is formed with excellent properties.

In collaboration with Hitachi Global Storage Technologies ferromagnetic bilayers are studied where field-induced tailoring of the exchange bias is achieved. Here, set fields imprint spin states which evolve when consecutively cycled hysteresis loops are measured. Understanding this aging or training effect impacts potential applications based on exchange bias.

Researchers at the University of Nebraska MRSEC in collaboration with their colleague from Strasbourg, France have demonstrated experimentally that the nature of AMR in nanoscale conductors is profoundly different due to ballistic mechanism of electron transport occurring in the absence of scattering. By measuring in-situ the ballistic conductance of Co electrodeposited nanocontacts at room temperature the researchers found that the conductance changes in a quantized fashion when the saturation magnetic field changes its direction as shown below.