Articoli in riviste
|Exchange bias like effect induced by domain walls in FeGd/FeSn bilayers|
|Canet F., Bellouard C., Mangin S., Chatelain C., Senet C., Siebrecht R., Leiner V., Piecuch M.|
|European Physical Journal B 34 (2003) 381|
|DOI : 10.1140/epjb/e2003-00235-y|
A study of exchange bias phenomenon in ferrimagnetic /ferromagnetic FeGd/ FeSn bilayers is presented. The amorphous FeSn and FeGd alloys have been grown by co-evaporation. Specific growth conditions allow to induce an uniaxial anisotropy in both alloys in a parallel direction. After saturation of the bilayers under a positive field, the hysteresis loop of one of the layer is shifted towards a positive field H E . The sign of the exchange bias field H E is shown to be due to the antiferromagnetic coupling between the net magnetizations of both alloys. The field H E is studied as a function of the thickness of each layer and of the temperature. Using ac-susceptibility measurements and polarized neutron reflectometry, it is shown that the reversal of magnetization of the bilayers is dominated by the presence of a domain wall at the interface. This exchange bias system is shown to act as a potential well for the magnetic domain wall. Within this assumption and thanks to a precise magnetic characterization of each alloy, the evolution of H E with the thickness of the layers is well reproduced using simple one-dimensional analytical models for the domain wall or a more elaborate numerical approach.