The FePt system has important perspectives as high-temperature corrosion-resistant magnets. In the form of rapidly solidified melt-spun ribbons, FePt-based magnets may exhibit in certain cases a two-phase hard–soft magnetic behaviour. The present paper deals with a microstructural and magnetic study of FePtAgB alloys with increasing Ag content. The aim is to identify and confirm the effect of Ag addition in decreasing the temperature of the FePt disorder–order structural phase transformation. A detailed high-resolution transmission electron microscopy study is employed, and the alternative disposal of hard and soft regions within the two-phase microstructure is observed and interpreted with respect to the X-ray diffraction results. In the as-cast Ag-containing samples, it is shown that there is an optimum of the Ag content for which best magnetic properties are obtained. Ag addition creates a nonlinear behaviour of the coercive field and the ordering parameter, similar to the RKKY interaction-induced interlayer exchange coupling (IEC) observed in magnetic layers separated by non-magnetic spacer layers. Direct formation of the L1₀ phase from the as-cast state in the FePtAgB alloys is reported with magnetic parameters compatible to other exchange spring permanent nanomagnets. These findings open novel perspectives into utilization of such alloys in applications requiring magnets operating in high-temperature industrial environments.

The growth of submonolayer metallic or molecular nanostructures via ion beam sputtering onto reconstructed semiconductor surfaces followed by in situ scanning probe imaging of the formed nanostructures provides an interesting basis for future development of new molecular multifunctional nanoarchitectured materials for various applications. The observed growth modes, structure and topology of pentacene, which is one of the most important candidates in the field of organic thin film electronic molecules, and Au metallic nanostructures deposited in the submonolayer regime onto reconstructed InP (0 0 1) surface, are discussed. During the initial stages of growth, a uniaxial diffusion channel dominates, and long pentacene molecular chains self-organise parallel to the [110] crystallographic direction on the InP surface. The study is performed by in situ non-contact atomic force microscopy (AFM) investigations with atomic resolution. It is shown that self-assembling of molecular structures onto flat terraces is dependent on the flatness and orientation of the terraces reconstructed onto the semiconductor surface. Moreover, it is possible to create functional molecular nanoarchitectures by nanomanipulation of single molecules with the AFM tip. This procedure may have large impact for technological applications such as organic thin film transistors and molecular nanowires.

A methodology for the quantitative estimation of the drug loading of iron oxide-based magnetic nanoparticles by corroborating magnetometry and Mössbauer spectroscopy investigations is reported. The proposed methodology is exemplified in the case of two series of nanoparticles, namely Fe₃O₄ nanoparticles covered with citric acid molecules and further functionalized with doxorubicin, and Fe₃O₄ nanoparticles covered with L-Cysteine molecules and further functionalized with doxorubicin. The general idea of the proposed methodology is to probe the real magnetic structure of the magnetic core via low-temperature Mössbauer spectroscopy for the correct estimation of the spontaneous magnetization of the magnetic core. It subsequently uses the ratio between the spontaneous magnetization of the covered nanoparticles and that of the magnetic core for the reliable and nondestructive evaluation of the nanoparticle loading by organic molecules. Although the methodology is exemplified in the case of magnetite-based nanoparticles, it can be successfully considered for a large class of medicine-loaded Fe-containing magnetic nanoparticles where ⁵⁷Fe Mössbauer spectroscopy can be applied.