MBE GROWTH AND FMR, BLS AND MOKE STUDIES OF EXCHANGE COUPLING IN FE WHISKER CR/FE(001) AND IN FE/CU/FE(001) LOOSE SPIN STRUCTURES/

The exchange coupling has been studied in structures which consist of two ferromagnetic layers separated by non-ferromagnetic spacers (trila yers), The exchange coupling was measured using FMR and BLS techniques in the temperature range 77-400 K. Two systems were investigated: (a) Fe whisker/Cr/Fe(001) and (b) Fe/Cr/Fe(001), The oscillatory thicknes s dependence of the exchange coupling through a spin-density wave Cr s pacer will be discussed and compared with recent data obtained by othe r groups, Cu interlayers were deposited either in a pure form, or a si ngle monolayer of Cu/Fe alloy ('loose spins') was inserted between two pure bcc Cu(001) layers. Several such 'loose spin' structures were en gineered to test the behavior of 'loose spin' structures, It was found that the presence of Fe impurity atoms has a strong tendency to decre ase the direct bilinear exchange coupling, The contribution of 'loose spins' to the exchange coupling can be made significant, and even domi nant, by a suitable choice of the RKKY coupling energy between the 'lo ose spins' and the surrounding ferromagnetic layers.