gmr stacks having a fe 66 ni 34 free layer except for fl2 the other parts of the full gmr stack have been kept the same table i sample fl1 fl2 bs r a dr r a 10 u00e5 cofe 10 30 u00e5 nife 18 0 349 2 4 17 b 10 u00e5 cofe 10 17 u00e5 feni 34 0 272 2 3 21 c 10 u00e5 cofe 10 25 u00e5 feni 34 0 419 2 4 20 in table i 0 6 u03bcm circle devices were used these had a tmr structure of seed layer antiferromagnetic layer cofe ru cofe alox fl1 fl2 capping layer fl2 was permalloy ni82fe18 for sample a and feni 34 at for samples b and c r a is given in units of ohm u00b7 u03bcm 2 bs values were measured on full film samples it can be seen that mr ratio is significantly enhanced with the new composite free layer structure since the mr ratio is usually determined by the spin polarization of magnetic layers interfacing with barrier layer the enhancement mr with new fl2 material indicates that fl2 material can affect spin polarization of fl1 through inter diffusion or modification of band structure another example of new composite free layer structure is fl1 feni 34 nife 18 by varying the relative thicknesses of feni 34 and nife 18 we can obtain high mr ratio low adjustable magnetic softness and suitable magnetostriction some examples are shown in table ii below table ii fl2 bs hc lambda 12cofe 10 25nife 66 0 46 12 47 8 5e u2212 06 10cofe 10 10nife 66 25nife 18 0 47 4 3 9 0e u2212 06 5cofe 10 10nife 66 40nife 18 0 54 2 9 7 0e u2212 06 the implementation of the.