Ferromagnetism in certain alloys consisting of magnetic and nonmagnetic species can be activated by the presence of chemical disorder. This phenomenon is linked to an increase in the number of nearest-neighbor magnetic atoms and local variations in the electronic band structure due to the existence of disorder sites. An approach to induce disorder is through exposure of the chemically ordered alloy to energetic ions; collision cascades formed by the ions knock atoms from their ordered sites and the concomitant vacancies are filled randomly via thermal diffusion of atoms at room temperature. The ordered structure thereby undergoes a transition into a metastable solid solution. Here we demonstrate the patterning of highly resolved magnetic structures by taking advantage of the large increase in the saturation magnetization of Fe60Al40 alloy triggered by subtle atomic displacements. The sigmoidal characteristic and sensitive dependence of the induced magnetization on the atomic displacements manifests a sub-50 nm patterning resolution. Patterning of magnetic regions in the form of stripes separated by ∼ 40 nm wide spacers was performed, wherein the magnet/spacer/magnet structure exhibits reprogrammable parallel (↑/spacer/↑) and antiparallel (↑/spacer/↓) magnetization configurations in zero field. Materials in which the magnetic behavior can be tuned via ion-induced phase transitions may allow the fabrication of novel spin-transport and memory devices using existing lateral patterning tools.

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The isothermal oxidation behaviour of Cr 2 AlC-MAX phase (ternary alloy with general formula M nz1 AX n : M5early transition metal, A5A-group element, mostly IIIA or IVA, X5C or N, n51-3) films on alumina substrates was investigated at temperatures between 700 and 1200uC for hold times of 1 to 30 h. The influence of the annealing temperature and time on the structure, surface morphology and microstructure evolution was studied. It was found that two processes occur simultaneously in these layers. These are the transformation of the disordered solid solution (Cr,Al) 2 C x to the ordered Cr 2 AlC-MAX phase and the oxidation of the MAX phase. In this work, a detailed discussion of these processes is given. Moreover, a schematic model of the associated structural and chemical changes in the annealed Cr 2 AlC layers based on the X-ray diffraction (XRD), Energy Dispersive X-ray (EDX), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and magnetic results was developed.

The isothermal oxidation behaviour of Cr 2 AlC films deposited with 0?1-0?3 at.%Y addition on alumina substrates was investigated at temperatures between 700 and 1200uC for hold times of 1 to 30 h. It was found that the Y atoms impede the bulk diffusion of Al and Cr atoms and, thus, the initial transformation of the disordered solid solution (Cr, Al) 2 C x to the ordered Cr 2 AlC-MAX phase. It also reduces the oxidation rate of the ordered Cr 2 AlC-MAX phase and promotes the a-Al 2 O 3 phase formation relative to the other alumina on the surface and leads to better adhesion of the layers. 0?3 at.%Y was found to promote the formation of a-Al 2 O 3 relative to the other possible phases most strongly for 700-900uC. However, 0?2 at.%Y addition was found to cause the best oxidation resistance at 1200uC. The model introduced in part I was developed further.

Polycrystalline Cu3-xP was successfully synthesized in different ionic liquids comprising imidazolium and phosphonium cations. The reaction of elemental copper and red phosphorus in trihexyltetradecylphosphonium chloride at 200 °C led to single-phase Cu3-xP (x = 0.05) within 24 h with a quantitative yield (99%). Liquid-state nuclear magnetic resonance spectroscopy of the ionic liquids revealed degeneration of the imidazolium cations under the synthesis conditions, while phosphonium cations remain stable. The solid products were characterized with X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, solid-state nuclear magnetic resonance spectroscopy, and elemental analysis. A reinvestigation of the electronic transport properties of Cu2.95(4)P showed metallic behavior for the bulk material. The formation of CuP2 during the synthesis of phosphorus-rich Cu3-xP (x ≥ 0.1) was observed.