Controlling the crystalline and magnetic texture in sputtered Fe0.89Ga0.11

Abstract

In this work we present a careful study on the relationship between the magnetic and structural properties of a highly magnetostrictive Fe 0.89 Ga 0.11 (Fe-Ga) alloy deposited onto glass, Si and MgO substrates. When grown on glass, the films are polycrystalline with randomly oriented grains without any texture, while the ones on Si and MgO present preferred growth directions. Fe-Ga/Si films show a [113] fibre-like texture, and Fe-Ga/MgO presents a quasi monocrystalline behavior with the (100) film plane direction parallel to the substrate surface. When Fe-Ga/MgO films are annealed an additional (110) texture is also observed. Magnetometry and ferromagnetic resonance (FMR) show that the magnetic behavior is closely related to the structural observed textures. Furthermore, the structural analysis allowed us to get a deeper understanding of the magnetic behavior. This point is very important to get the ability of controlling the crystalline texture by means of growing onto different substrates and/or thermal treatments, which in turns opens the possibility of handling the magnetic texture which is particularly important in magnetostrictive materials for electronic devices.

Magnetoelasticity of Fe1−xGax thin films on amorphous substrates

“…Composition values measured in the samples were consistently lower than the nominal composition of the targets. This Ga loss during the growth process has been previously reported [29,34,35] and was attributed to the growth kinetics [29,36]. The composition (x Film Fe , x Film Ga ) and thickness values of the samples are also summarized in Table I.…”

“…The diffractograms were refined by a simple full pattern Rietveld-type refinement model that has been developed to extract accurate lattice parameters, a, from a single XRD measurement of a textured multiphase sample [29]. We have found that a values increase slightly with the Ga concentration for A 2 Fe-Ga samples.…”

“…In Ref. [29], we have shown that the crystal grain structure can be controlled by the substrate type. For monocrystalline cubic substrates, the samples present a structural anisotropy in the plane due to substrate symmetry, which implies the existence of two independent MEC coefficients [12,13], while on amorphous substrates [or monocrystalline wafers with a native oxide, as on Si (100)], the samples present an isotropic behavior in the plane that can be described with a single MEC coefficient [19,24].…”

Local and Medium Range Order Influence on the Magnetic Behavior of Sputtered Ga-Rich FeGa Thin Films

“…27 Another key parameter in the sputtering technique is the growth power, tightly related to the growth rate that influences the microstructure and morphology of films at different scales. [28][29][30][31] In this work we address the influence of the growth power on Ga-rich FeGa thin films sputtered in the ballistic regime, in which we have observed that it is possible to fix the Ga content within a very narrow range. This allows us to better correlate the microstructure (medium and local range) promoted during sputtering growth with the magnetic properties of the layers.…”

“…The ballistic flow regime increased the amount of ordered phases with respect to the diffusive, while the direction of the uniaxial magnetic easy axis seems to be set by the oblique incidence. , Actually, Zhang and co-workers have recently reported its use for controlling the magnetic anisotropy in exchange-biased InMn/FeGa bilayers . Another key parameter in the sputtering technique is the growth power, tightly related to the growth rate that influences the microstructure and morphology of films at different scales. − …”