Eur. Phys. J. Plus (2017) 132: 58
https://doi.org/10.1140/epjp/i2017-11327-x

Regular Article

Influence of the surface morphology on the magnetoresistance of ultrathin films of ferromagnetic metals and their alloys

¹ 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

^* e-mail: y.shabelnyk@aph.sumdu.edu.ua

Received: 7 September 2016
Accepted: 4 January 2017
Published online: 31 January 2017

Abstract

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.