Giant magnetostriction in amorphous (Tb1−xDyx)(Fe0.45Co0.55)y films

Abstract

The magnetization and magnetostriction have been studied in amorphous (Tb1−xDyx)(Fe0.45Co0.55)y films. A well-defined easy axis is created by magnetic field annealing and the sperimagnetic cone structure, characteristic of these amorphous alloys, is reduced. The anisotropy has a minimum at x=0.73 as in the R Fe2 Laves phase. This points to the similarity between the local environments in the amorphous and crystalline states. A giant magnetoelastic coupling coefficient b of 60 MPa is developed at 300 K in low applied field for x=0, optimally annealed films. Assuming a Young’s modulus and a Poisson ratio of 80 GPa and 0.31, respectively, the magnetostriction is evaluated at 1020×10−6. This is much larger than previously reported values in other amorphous films.

Nanostructure and magnetization reversal process in TbFeCo/Yx(FeCo)1−x spring-magnet type multilayers

“…For all samples, the magnetostriction obtained is comparable to the value deduced from the data of the single-layer Terfecohan samples, e.g. l TbFeCo B10 À3 [9][10][11][12] using the following expression [2][3]6]:…”

Magnetostrictive twisting of film–substrate plates

“…The film and the substrate have the following properties: E f =80 GPa, n f =0.31, l s ¼ 1020 Â 10 À6 ; E s ¼ 130 GPa; n s =0.28 [12]. Using data for the bimorphs fabricated by Garnier et al [13], the thicknesses of the film and the substrate are taken to be t f ¼ 2 mm; t s ¼ 15 mm: The initial magnetization of the film is assumed to be randomly distributed in three dimensions.…”

Magnetostrictive properties of amorphous SmCo thin films with imprinted anisotropy

“…Amorphous films of the same * fridrik.magnus@physics.uu.se material exhibit lower magnetostriction, albeit at lower fields due to a reduced anisotropy [16,17]. Other high-anisotropy materials [18] such as crystalline SmCo also have a large magnetostriction although it is strongly dependent on the grain size [19].…”