Tuning high frequency magnetic properties and damping of FeGa, FeGaN and FeGaB thin films

Abstract

A series of FeGa, FeGaN and FeGaB films with varied oblique angles were deposited by sputtering method on silicon substrates, respectively. The microstructure, soft magnetism, microwave properties, and damping factor for the films were investigated. The FeGa films showed a poor high frequency magnetic property due to the large stress itself. The grain size of FeGa films was reduced by the additional N element, while the structure of FeGa films was changed from the polycrystalline to amorphous phase by the involved B element. As a result, N content can effectively improve the magnetic softness of FeGa film, but their high frequency magnetic properties were still poor both when the N2/Ar flow rate ratio is 2% and 5% during the deposition. The additional B content significantly led to the excellent magnetic softness and the self-biased ferromagnetic resonance frequency of 1.83 GHz for FeGaB film. The dampings of FeGa films were adjusted by the additional N and B contents from 0.218 to 0.139 and 0.023, respectively. The combination of these properties for FeGa films are helpful for the development of magnetostrictive microwave devices.

Magnetization enhanced the multiple magnetic domain-dominated resonance modes in stripe domain films

“…In figure 5(a), no obvious resonant absorption peak can be observed for the 110 nm-thick film, and the corresponding field-dependent spectra (figure 6(a)) also do not reveal an obvious increasing frequency signal with the increases of H app . This 'flat' magnetic spectrum is attributed to the weak in-plane anisotropy and the large H c of this film (see figure 4(a)), which suppress the dynamic permeability [76,83]. In this work, the H c of 110 nm FeCoHf film is ∼14 mT, and there is also no obvious resonant peak.…”

Magnetic Properties Regulation of FeGa and FeGaNi Films with Oblique Magnetron Sputtering

“…However, the magnetic anisotropy becomes obvious with the increase in the α angle. This indicates that in-plane anisotropy can be induced by oblique sputtering for the internal stress in FeGa films [9,31]. Meanwhile, in Figure 4b, FeGaNi films show narrower hysteresis loops and relatively stronger in-plane magnetic anisotropy compared with FeGa, which means that doping Ni can improve the soft magnetic property of FeGa films.…”

“…It can be clearly seen that all the films display a strong diffraction peak at 44.6 • corresponding to the bcc (110) diffraction peak and two weak peaks at 65 • and 82 • corresponding to the bcc (200) and (211) diffraction peaks for FeGa or FeGaNi films, illustrating a common polycrystalline structure. The strength of the peaks indicates that the growth direction is a slight preferred orientation along (110) [9,32,33]. The position and shape of the peaks have no clear change.…”

“…FeGa, with its bcc structure and crystallographic orientation to (110), is usually preferred for obtaining good magnetostrictive properties [5]. This has attracted widespread studies focusing on FeGa materials for strain-mediated magnetoelectric devices [6][7][8][9][10]. Meanwhile, compared with traditional magnetostrictive materials, such as TbDyFe, FeGa shows soft magnetic properties.…”

Anisotropy in thin film galfenol deposited on LiNbO3 as measured by MOKE

“…Additionally, weak anisotropy has been induced during film growth by sputtering using low argon pressure (∼3µbar) [11], or alternatively by raising the substrate temperature to several hundred de-40 grees Celsius during deposition [12,13]. Doping Fe-Ga films with B, and N has also been found to induce a large stress which affects the magnetic and high frequency response of the films [14].…”