Crystal Structure and Physical Properties of Artificial Metallic Multilayrs with Non-equilibrium Crystal Structure of 3d Trandition Metals

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Artificial metallic multilayrs of [fcc-Fe/Cu], [gamma-Fe/Cu(Ni)], [gamma-Fe(Ni/Cu], [Fcc-Cr/Cu], [bct-Ni/Fe], [bcc-Cu/Fe], [bct-Ni/Cr], [bcc-Cu/Fe], [bcc-Fe/Cr], [bct-Ni/Cr], [hcp-Co/Cr], [fcc-Au/bcc-Fe], [bct-Cu/bct-Fe(Ni)], [bct-Cu/bcc-Fe(Co)] were prepared by MBE or IBS method.The rach atomic layrs in the multilayr were controlled within several atomic layrs. non-equilibrium crystal structure and the transition to the equilibrium state were precisely anakyzed. The magnetic properties and magnetoresistance were inverstigated . The main results were as follows.1. The fcc-Fe transforms to high spin state when Fe is deposited on Cu (001) because of restriction of interatomic distance between Cu atoms at interfaces. The application of high spin to low spin state transtion of fcc-Fe to the magnetic recording media were investigated.2. Ni layr less than 3ML deposited on bcc-Fe (001) or bcc-Cr (001) is bct structure. And the Ni layr more than 4ML takes c(2+2) like structure and finally the crystal structure of Ni layr transforms to a domain structure of fcc-Ni. The magnetic moment of bct-Ni is more than that of bulk fcc-Ni. The magnetic properties of bcc-Cu and fcc-Cr are non-ferromagnetism.3. Crystal structures of Fe, Co and Ni on bcc-Cr (001) were bcc, hcp, bct within several ML,respectively. Magnetoresistance (MR) ratio of these multilayrs were 116%, 2%, and less than 0.1% for Fe, Co and Ni, resoectively. The origin of the large difference in MR ratio were discussed considering the interface effect.4. The MR ratio of the annealed [bcc-fcc] multilayrs were increased up to twice comparing with as-deposited films.