Epoxy-Containing Ionic Liquids with Tunable Functionality.

New types of ionic liquids (ILs) with an epoxy group on a piperidinium-type cation were successfully synthesized by the simple anion exchange reaction of a solid 1-allyl-1-(oxiran-2-ylmethyl)piperidinium bromide, which was designed in this study. Unfortunately, the physicochemical properties, e.g., viscosity and ionic conductivity, of the ILs were inferior to those of common ILs such as 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C4mim][Tf2N]). However, the resulting ILs are of great interest as reaction intermediates: For example, the epoxy group on the cation could react with various reagents, including CO2. Consequently, the modification of the cation structure in the ILs was possible. This is particularly interesting because it is very difficult to modify commonly used ILs. The approach established in this article will provide a favorable synthetic route for creating novel functional ILs in the future.

Conversion of FeCo from soft to hard magnetic material by lattice engineering and nanopatterning.

The development of magnetic materials with large uniaxial magnetic anisotropy (K u) and high saturation magnetization has attracted much attention in various areas such as high-density magnetic storage, spintronic devices, and permanent magnets. Although FeCo alloys with the body-centred cubic structure exhibit the highest M s among all transition metal alloys, their low K u and coercivity (H c) make them unsuitable for these applications. However, recent first-principles calculations have predicted large K u for the FeCo films with the body-centred tetragonal structure. In this work, we experimentally investigated the hard magnetic properties and magnetic domain structures of nanopatterned FeCo alloy thin films. As a result, a relatively large value of the perpendicular uniaxial magnetic anisotropy K u = 2.1 × 106 J·m-3 was obtained, while the H c of the nanopatterned FeCo layers increased with decreasing dot pattern size. The maximum H c measured in this study was 4.8 × 105 A·m-1, and the corresponding value of µ 0 H c was 0.60 T, where µ 0 represented the vacuum permeability.