Influence of the surface morphology on the magnetoresistance of ultrathin films of ferromagnetic metals and their alloys
Department of Applied Physics, Sumy State University, 2 Rimsky-Korsakov Str., 40007, Sumy, Ukraine
2 Department of Physics and Methods of Teaching Physics, Sumy State Pedagogical University named after A.S. Makarenko, 87 Romenska Str., 40002, Sumy, Ukraine
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Accepted: 4 January 2017
Published online: 31 January 2017
The microstructure, morphology and magnetoresistive properties of as-deposited and annealed at 700K discontinuous films of ferromagnetic metals and their alloys are investigated. It is established that the isotropic field dependences stemming from the spin-dependent electron tunneling between ferromagnetic islands are observed for as-deposited Co films with an effective thickness (d) of d Co = 5-25 nm as well as for Fe films (d Fe = 10-30 nm). It is shown that the maximum values of the isotropic magnetoresistance take place in the case when the size of the islands is equal to 3-5nm and the width of the dielectric barrier between them is 1-3nm. The maximum TMR values for the films annealed at 700 K are obtained when the dielectric barrier is 2-5 nm wide.
© Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg, 2017