Size effects in thin antiferromagnetic layers and "ferromagnet - nonmagnetic metal" multilayers

Alexander I. Morosov ,  Alexey A. Berzin ,  Alexander S. Sigov 

Moscow State Institute of Radioengineering, Electronics, and Automation (Technical University) (MIREA), pr. Vernadskogo, 78, Moscow 119454, Russian Federation

Abstract

Peculiarities of spin-flop and spin-flip transitions in thin antiferromagnetic layers and “ferromagnet – nonmagnetic metal” multilayers were investigated by numerical modelling methods. In supposition that ferromagnetic layers in multilayer are magnetized homogeneously the behaviour of “ferromagnet – nonmagnetic metal” multilayer in external magnetic field is completely analogous to the behaviour of antiferromagnetic layer with parallel noncompensated surfaces.
The character of spin-flop transition in antiferromagnetic layer of nanometre scale thickness (“ferromagnet – nonmagnetic metal” multilayer with antiferromagnetically coupled ferromagnetic layers) strongly depends upon a number of atomic planes (ferromagnetic layers) parity. We have found that in the case of even number of atomic planes in the antiferromagnetic layer, the spin-flop phase transition of the first order takes place in the surface spin-flop transition field which is 21/2 times smaller than the bulk one [1,2]. As a result the state with domain wall in the layer centre arises.
In the case of odd number of atomic planes in the antiferromagnetic layer the second order spin-flop phase transition occurs in the magnetic field higher than the bulk spin-flop one. The spin-flip transition in the layer with arbitrary atomic planes number parity takes place in the magnetic field lower than the bulk spin-flip one. The spin-flop and spin-flip phase transition field dependences upon number of atomic planes (ferromagnetic layers) were found.

This work is partially supported by CRDF – RF Ministry of Education and Science Award VZ-010-0.

[1] D.L. Mills. Phys. Rev. Lett. 20, 18 (1968).
[2] F. Keffer, H. Chow. Phys. Rev. Lett. 31, 1061 (1973).

 

Presentation: poster at E-MRS Fall Meeting 2005, Symposium D, by Alexander I. Morosov
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-03-16 15:54
Revised:   2009-06-07 00:44