[12a-A405-1~11] 12.2 評価・基礎物性

▲ [12a-A405-11] Magneto-Optical Surface Plasmon Resonance in Ferromagnetic/Noble Metal Superlattices

〇(D)Muhammad Arifin^1,2、Toru Akiyama¹、Tomonori Ito¹、Kohji Nakamura¹ (1.Mie Univ., Japan、2.Gadjah Mada Univ., Indonesia)

キーワード：magneto-optical surface plasmon resonance, first-principles calculations, enhancement

Magneto-optical (MO) effect allows to improve a sensitivity in surface plasmon resonance (SPR) biosensor where the MO effect increases at the SPR angle so as that the reflectance falls sharply. In the present work, we have demonstrated a giant enhancement of the magneto-optical surface plasmon resonance (MOSPR) in ferromagnetic Fe/noble (M=Cu, Ag, Au) metal superlattices, Fe_x/M_x, where x is the number of atomic-layers, form first-principles calculations. Calculations were carried out by using a full-potential linearized augmented plane wave (FLAPW) method [1], and the diagonal and off-diagonal parts of the absorptive optical conductivity tensor, Re(σ_xx) and ωIm(σ_yz), were estimated by linear response theory. In an optical range (1.6 – 3.3 eV), the Re(σ_xx) of Fe_xCu_x is much larger than those of Fe_xAu_x and Fe_xAg_x. In Fe_xCu_x, Re(σ_xx) increases in proportion to the number of x. The spectrum ωIm(σ_yz) on Fe_xAu_x shows the peak shift from the energy position of 2.0 eV to 2.7 eV and 3.3 eV for x =1, 2 and 3, respectively. Assumed the Kretschmann configuration with the 4 × 4 transfer matrix method [2], we have simulated the MOSPR by using gelatin as a sample. The resonance condition in the SPR spectra occurs at an incident angle of 75°, which is in agreement with our previous experiments [3]. On the other hand, the transverse magneto-optical Kerr effect (TMOKE) signal, ΔR_pp/R_pp, in the resonance condition increases proportionally to the number of x in Fe_xM_x. Additionally, a significant enhancement of the TMOKE signal, by 120%, is observed in Fe₃Cu₃, where the enhancement is mainly due to the MO activity [4]. Further discussions will be presented.