The surface-to-volume ratio: a key parameter in the thermoelectric transport of topological insulator Bi2Se3 nanowires.

We systematically investigated the role of topological surface states on thermoelectric transport by varying the surface-to-volume ratio (s/v) of Bi2Se3 nanowires. The thermoelectric coefficients of Bi2Se3 nanowires were significantly influenced by the topological surface states with increasing the s/v. The Seebeck coefficient of Bi2Se3 nanowires decreased with increasing the s/v, while the electrical conductivity increased with increasing the s/v.

Magnetic domain pattern in hierarchically twinned epitaxial Ni-Mn-Ga films.

Magnetic shape memory alloys exhibit a hierarchically twinned microstructure, which has been examined thoroughly in epitaxial Ni-Mn-Ga films. Here we analyze the consequences of this 'twin within twins' microstructure on the magnetic domain pattern. Atomic and magnetic force microscopy are used to probe the correlation between the martensitic microstructure and magnetic domains.

Magnetic materials and devices for the 21st century: stronger, lighter, and more energy efficient.

A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy efficiency in the total energy lifecycle, has accelerated research into energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the efficiency and performance of devices in electric power generation, conditioning, conversion, transportation, and other energy-use sectors of the economy. This review focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials, with an emphasis on their optimization for energy applications.

Fracture mechanisms in bulk metallic glassy materials.

We find that the failure of bulk metallic glassy (BMG) materials follows three modes, i.e., shear fracture with a fracture plane significantly deviating from 45 degrees to the loading direction, normal tensile fracture with a fracture plane perpendicular to the loading direction, or distensile fracture in a break or splitting mode with a fracture plane parallel to the loading direction.