We have achieved (001) oriented L10 (Fe1−xCux)55Pt45 thin films, with magnetic anisotropy up to 3.6 × 107 erg/cm3, using atomic-scale multilayer sputtering and post annealing at 400 °C for 10 s. By fixing the Pt concentration, structure and magnetic properties are systematically tuned by the Cu addition. Increasing Cu content results in an increase in the tetragonal distortion of the L10 phase, significant changes to the film microstructure, and lowering of the saturation magnetization and anisotropy. The relatively convenient synthesis conditions, along with the tunable magnetic properties, make such materials highly desirable for future magnetic recording technologies.

L 1 0 granular FePt–SiO2 films with a (001) preferred orientation and well-separated grains of 5.14nm were obtained by depositing atomic-scale Fe∕Pt∕SiO2 multilayers (MLs) on glass substrates and subsequently annealing MLs at a temperature of 350°C. Large out-of-plane coercivity of 7700Oe and a high ordering factor of 0.83 were achieved. Alternate atomic-scale depositions promoted the formation of (001) textures. Furthermore, because of the low surface energy of SiO2 layers, SiO2 tended to diffuse into grain boundaries of FePt during annealing, which may accelerate diffusion of Fe and Pt atoms, resulting in the low-temperature ordering.

Highly ordered single-crystalline (001) FePt nanoparticles (NPs) with controllable sizes and a well-aligned easy axis were obtained by tuning the layer numbers and the SiO2-layer thickness of atomic-scale [Fe/Pt/SiO2]n multilayers deposited on SiO2∥Si substrates. After 700 °C annealing, quasi-self-assembled NPs with ultrahigh areal density of 1.0×1013 dots/in.2 and large out-of-plane coercivity (Hc,⊥) of 31 kOe were achieved. All particles were embedded into the SiO2 substrates due to the low surface energy of SiO2, which significantly prevented the coarsening during annealing and resulted in a reduced particle size of 5.6 nm and small size distribution of 14.1%.

Recent studies on the mechanisms by which topologically knotted proteins attain their natively knotted structures have intrigued theoretical and experimental biophysicists. Of particular interest is the finding that YibK and YbeA, two small trefoil knotted proteins, remain topologically knotted in their chemically denatured states. Using small-angle X-ray scattering (SAXS), we examine whether these chemically denatured knotted proteins are different from typical random coils. By revisiting the scaling law of radius of gyration (Rg) as a function of polypeptide chain length for chemically denatured proteins and natively folded proteins, we find that the chemically denatured knotted proteins in fact follow the same random coil-like behavior, suggesting that the formation of topological protein knots do not necessarily require global compaction while the loosely knotted polypeptide chains are capable of maintaining the correct chirality without defined secondary or tertiary structures.