Single-phase α''-Fe16N2 nanoparticles have been synthesized with high reproducibility in gram amounts for the first time. The nanoparticles were obtained through the various kinds of successive procedure starting from the reduction of Fe-oxides, followed by nitriding in an atmosphere with very low moisture and oxygen contents of less than 1 ppm through the entire process. The single-phase α''-Fe16N2 nanoparticles exhibited saturation magnetization (Ms) of 234 emu/g at 5 K and a magnetocrystalline anisotropy constant (Ku) of 9.6×106 erg/cm3. These magnetic properties of this α''-Fe16N2 nanoparticles suggest that a new path for a possible candidate of the rare-earth-free permanent magnet material with a high Ms.

Nanoparticles of R-Fe, an excellent soft magnet, have been successfully made corrosion-resistant and dispersible in polar and nonpolar solvents by coating these with inner and outer layers of amorphous silica and organics like poly(ethylene glycol), respectively. The double coating was facilitated by using stable and easy-to-handle oxide particles as the core to be subsequently metallized at temperatures low enough to keep the organic layer intact. Use of CaH 2 as a reductant lowered the working temperature down to 200-300 °C, where thermal particle adhesion did not take place, formation of impurities like iron silicates was suppressed, and the overall morphological features of the starting particles were preserved. The feasibility of organo-functionalization of the surface will open a way for this nanomagnet toward bioscientific and medical applications.

Understanding the behavior of ferroelectric response in zero-dimensional systems, that is, under three-dimensional quantum confinement, is an important task from the technological point of view, which might lead to further miniaturization of electrical devices. Evidently, carrying out direct electrical measurements on ideal zero-dimensional nanoparticles is an extremely nontrivial process, although several experimental reports employing indirect methods have been published. However, the use of recently developed piezore-A C H T U N G T R E N N U N G sponse force microscopy (PFM) techniques, in conjunction with the careful choice of substrates and appropriate preparation of samples for measurements, makes it possible to experimentally observe this phenomenon on nearly ideal dimensionless systems.Ferroelectric (FE) systems belong to an extremely important class of materials because of the possibility of utilizing them for fabricating ferroelectric random access memories (FERAMs) and microelectromechanical systems (MEMS), which stem from their associated pyro-, piezo-, and ferroelectric properties. In comparison with bulk ferroelectric materials, lower-dimensional structures promise to increase the efficiency of such devices to a large extent and, therefore, future development of the electronics industry strongly requires a clear understanding of the relationship between properties and particle sizes. The key question is whether the ferroelectric phase transitions and multistable states still exist in lower dimensions or not. Previous theoretical studies [1] predicted that polarization values should be smaller in two dimensions (thin films) and below a certain [*] Dr.Figure 4. a, b) Top: Large-area and small-area AFM images along with corresponding thickness profiles from the deposits of samples A (a) and B (b), respectively. The hysteretic piezoresponse versus bias voltage curves from the samples are shown in the corresponding bottom panels, while the changes in phase angle with voltage are shown in the insets.

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