|Budget Amount *help
¥4,000,000 (Direct Cost : ¥4,000,000)
Fiscal Year 1996 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1995 : ¥2,900,000 (Direct Cost : ¥2,900,000)
1. Magneto-optical effects of rare earth (RE)-transition metal (TM) amorphous alloy films (1) Yb-Co amorphous alloy films are prepared, and the magnetic and magneto-optical properties are measured. It is estimated that the Yb atoms become 2+ ions instead of 3+. As the results, Yb atoms have no magnetic moment in the Yb-Co alloy and the magnetic and magneto-optical properties are very similar to those for La-Co and/or Ce-Co films.
(2) The magneto-optical Kerr effect is investigated for Gd-Co films with wide range of Gd content from 10 to 50 atomic percents. Different from other RE species, the atomic moment of Co decreases only slightly with the increase of Gd content, the fact which results in the relatively large Kerr rotation at higher Gd concentration. By analyzing the compositional dependence of the Kerr rotation, the contributions from both Gd and Co sub network magnetizations are separated and the spectra of the Kerr rotation coefficient are determined within the range of waveleng
th from 400 to 1,000nm.
(3) The magnetic structures of RE-TM amorphous alloys except RE=Eu are clarified using all available data including present project studies.
(4) The contributions of RE and TM sub networks on the Kerr rotation spectra are separated for RE-Fe_<0.8>Co_<0.2> alloy films, which are important media for magneto-optical memory.
2. Studies on the development of new magneto-optical materials of Mn compound and/or multilayrs
(1) A remarkable increase of Kerr rotation at low temperature, which cannot be explained by the existing theory, is found for MnBi films. The spectra of all components of dielectric constant tensor are calculated in the wavelength range of 230-1600nm at 85,300, and 475K from the data on the Kerr rotation, the Kerr ellipticity, optical reflectivity, and optical transmittance. The physical origins of the Kerr effect are discussed from the viewpoint of electronic structure. It is concluded that the giant Kerr rotation in MnBi is originated from the interband transition from 3d * to 3d * spin states of Mn.
(2) As for the development of new Mn compounds and/or artificial superstructures, any remarkable data have not yet been obtained, and the project is remained for further investigations.