|Budget Amount *help
¥8,700,000 (Direct Cost : ¥8,700,000)
Fiscal Year 1997 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1996 : ¥6,100,000 (Direct Cost : ¥6,100,000)
Since the structure at/near the interface of superlattices influences magnetic property, it is important to investigate details of the structure. In the crystal growth, continuity of the crystal lattice is one of the interesting points. The reflection high energy electron diffraction (RHEED) allows us to investigate the surface structure during the crystal growth. The RHEED system installed in our molecular beam epitaxy (MBE) system enables us to observe, continuously, the change of the surface in-plane lattice constant on a real-time basis. Thus we have investigated the crystal growth of [Co/NM] (NM=Au, Ag) binary superlattices and [M1/Co/M2] (M1, M2=Au, Cu) ternary superlattices. We have also investigated magnetic properties of [M1/Co/M2] ternary superlattices. Moreover, we discuss the relation between the perpendicular magnetic anisotropy and the interface structure. Here, the description [M1/Co/M2] means that the deposition sequence is of Co on M2 and M1 on Co/M2.
In the Co/Au superlattice, the in-plane lattice constant changes continuously Co on Au, while in the Co/Ag superlattice, that is discontinuous. Therefore, in the Co/Au superlattice the large lattice strain is introduced to the Co layrs, while in the Co/Ag superlattice little strain is contained. In the Cu/Co/Au and Au/Co/Cu superlattices consisting of the same kind of atomic species and the reverse deposition sequences, the lattice constants change continuously, but the amount of the change are different. Co in the Cu/Co/Au superlattice contains more elastic strain than that in the Au/Co/Cu superlattice. The Cu/Co/Au superlattice containing more elastic strain shows larger perpendicular mangetic anisotropy.