Sputter deposition of compositional gradient magnetostrictive FeCo based thin films

Giant magnetostriction in annealed Co1−xFex thin-films

“…The magnetostriction value of 67 p.p.m. obtained for our Co 0.5 Fe 0.5 films is in good agreement with previous polycrys talline thin film 10 and bulk 38 reports.…”

“…Interest in magnetostrictive films began in the mid 1970s 9 , and various single layer and multilayer magnetostrictive films exhibiting large magnetostriction have been reported to date 2,3,5,[10][11][12][13][14][15][16] . Among them, rare earth-Fe alloy thin films show the largest magneto striction including Tb-Dy-Fe films that can generate strains over 1,000 p.p.m.…”

“…for annealed bulk single crystal Fe 0.5 Co 0.5 alloys 29,30 . Since then, several studies on alloys of the 50:50 composition in bulk 31,32 and thin films 10,11,13,33 have been reported, but little atten tion has been given to the other compositions in the phase diagram. In a recent bulk experiment, magnetostriction of 150 p.p.m.…”

Magnetic properties of field-annealed FeCo thin films

“…A columnar structure has also been observed in the present samples through FESEM images. These compositions are characterized by a large positive magnetostriction value l s (E10 2 ppm) and a relatively large and negative first-order anisotropy constant K 1 (EÀ1.5 Â 10 À5 erg/cm 3 ) when in the disordered phase, and a smaller magnetostriction and vanishing first-order anisotropy constant when in the ordered phase [1,3,8].…”

Materials Optimization for Magnetic MEMS

“…Taking published data for the saturation magnetostriction constants of Fe Co [20], [21], an isotropic polycrystal should show a net magnetostriction constant of approximately 80 ppm. We have demonstrated [22] that this level of magnetostriction can be achieved in polycrystalline 300 nm thick films on glass substrates, but at the expense of coercivities greater than 500 A/m even after annealing. The anisotropy field was 3800 A/m.…”