We fabricated a one-dimensional magnetophotonic crystal (MPC), in which a magnetic layer of Co–ferrite (∼40 nm in thickness) is sandwiched by a couple of dielectric multilayer reflectors with (SiO2/TiO2)×7 structure. The Co–ferrite layer was synthesized by ferrite plating from aqueous solution at 90 °C. The MPC is so designed to enhance magneto-optical Faraday rotation θF at the Fabry–Pérot resonance wavelength λ of the multilayer structure. θF was observed to increase by factor of ∼5.4, but at λ=∼620 nm which is deviated from the target resonance (λ=740 nm) and at very weak transmissivity. This may be because the Co–ferrite layer is rough in surface and smaller in thickness than the target thickness at which Fabry–Pérot resonance is designed to occur.

Formation of anionic fluoride-complexes of element 104, rutherfordium, produced in the 248 Cm( 18 O, 5n) 261 Rf reaction was studied by anion-exchange on an atom-at-a-time scale. It was found that the hexafluoro complex of Rf, [RfF 6 ] 2− , was formed in the studied fluoride ion concentrations of 0.0005-0.013 M. Formation of [RfF 6 ] 2− was significantly different from that of the homologues Zr and Hf, [ZrF 6 ] 2− and [HfF 6 ] 2− ; the evaluated formation constant of [RfF 6 ] 2− is at least one-order of magnitude smaller than those of [ZrF 6 ] 2− and [HfF 6 ] 2− .

The extraction behavior of rutherfordium (Rf) into tributylphosphate (TBP) from hydrochloric acid (HCl) has been studied together with those of the lighter group-4 elements Zr and Hf. The extractability of

Polycrystalline iron oxide films, 0.1–1.1 μm in thickness, are synthesized on glass substrates at room temperature directly from an aqueous solution of FeCl2 by ferrite plating. The films have a single phase spinel structure of mixed solution (Fe3O4)1−x–(γ-Fe2O3)x, as revealed by x-ray diffractometer and conversion electron Fe57 Mössbauer spectroscopy. At room temperature the films exhibit negative magnetoresistance (MR) of ratio ΔR/R=−3.3% to −7.4%, which is ascribed to intergranular tunneling of spin polarized electrons of Fe3O4. The resistivity R of the films is 2.2×100–1.3×103 Ω cm, much higher than that (∼10−2 Ω cm) reported for bulk samples of Fe3O4; R and ΔR/R depend on the plating conditions and, therefore, the composition x in (Fe3O4)1−x–(γ-Fe2O3)x of the samples.

Chemical studies on element 104, rutherfordium (Rf), at JAERI (Japan Atomic Energy Research Institute) are reviewed. The transactinide nuclide 261 Rf has been produced in the reaction 248 Cm( 18 O, 5n) at the JAERI tandem accelerator with the production cross section of about 13 nb. On-line anion-exchange experiments on Rf together with the lighter homologues, group-4 elements Zr and Hf, in acidic solutions have been conducted with a rapid ion-exchange separation apparatus. From the systematic study of the anion-exchange behavior of Rf, it has been found that the properties of Rf in HCl and HNO 3 solutions are quite similar to those of Zr and Hf, definitely confirming that Rf is a member of the group-4 elements. However, we have observed an unexpected chemical behavior of Rf in HF solutions; the fluoride complex formation of Rf is significantly different from those of the homologues. Prospects of extending chemical studies on transactinide elements in the near future at JAERI are briefly considered.