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A simple and convenient method is demonstrated in this work by continuously applying uniaxial tensile strains to tune the high-frequency properties of flexible magnetic films. The magnetostriction effect causes the uniaxial magnetic anisotropy in the Ti/Fe/Ni81Fe19/Fe/Ti multilayer film when the flexible substrate transitions from the convex state to the planar state after preparation. In addition, the microstructure, magnetic domain morphology, and the high-frequency magnetic performance of the pre-strained Ti/Fe/Ni81Fe19/Fe/Ti multilayer films are investigated. The results show that the flexible Ti/Fe/Ni81Fe19/Fe/Ti multilayer films' initial permeability can be monotonically varied over a hundred units, and the resonant frequency can be adjusted around 1.5 GHz. The flexible Ti/Fe/Ni81Fe19/Fe/Ti films, with their elastic-tunable magnetic performance, are promising candidate materials for flexible microwave devices. [ABSTRACT FROM AUTHOR]

Large effective magnetic anisotropy and low coercivity are usually mutually exclusive in nanometer crystalline ferrite due to opposing dependencies on the grain size. Here, by applying a parallel magnetic field during sputtering, NiZnCu ferrite thin films with larger effective magnetic anisotropy, as well as lower coercivity and an ideal permeability spectrum were prepared through adjustment of exchange length Lex. A (400) preferred orientation and a declined lattice constant triggered by the magnetic field were observed, and the cation redistribution was thoroughly discussed by XRD intensity calculation in which iron ions presented a tendency to occupy the octahedral site. By collective effects of grain growth promotion and enlarged anisotropy energy, the inducing magnetic field permitted samples with invariant stoichiometric composition a higher initial permeability and a broader working frequency range. These findings provide a valuable reference for effectively tuning magnetic properties of the magnetic thin films that are promising for high-frequency applications. [ABSTRACT FROM AUTHOR]

Motivated by the wide application of the antiferromagnetic/ferromagnetic (FM) bilayer structures in high-frequency microwave magnetic devices, the Si/NiO/Ni81Fe19 films with different orientations of NiO buffer layer are deposited by magnetron sputtering technology. The phase, microstructure, hysteresis loop, and angular dependence of FM resonance (FMR) linewidth are investigated by X-ray diffractometer, field-emission scanning electron microscope, atomic force microscope, vibrating sample magnetometer, and electron spin resonance spectrometer, respectively. The Si/NiO(220) film has much smaller grain size than that of Si/NiO(200) film, which is beneficial to grow a high quality NiFe film on Si/NiO(220)/NiFe bilayer structures. The hysteresis loop of Si/NiO(220)/NiFe films shows an obvious exchange bias and a relatively smaller coercivity. The FMR linewidth ( \Delta H ) of Si/NiO(220)/NiFe films is much smaller than that of Si/NiO(200)/NiFe films, which is caused by the different structural properties and morphologies of the NiO buffer layer. The Landé $g$ factors and effective damping parameters \alpha_{\rm eff} are also discussed. [ABSTRACT FROM AUTHOR]

This work demonstrates the dependence between magnetic properties and the thickness of NiFe thin films. More importantly, a quantitative study of the surface composition of NiFe thin film exposed to atmospheric conditions has been carried out employing angle-resolved X-ray photoelectron spectroscopy (ARXPS). In this study, we fabricated Ni81Fe19 (NiFe) thin films on Si (100) substrate using electron beam evaporation and investigated their surface morphologies, magnetic properties, and the thickness of the surface oxide layer. The coexistence of metallic and oxidized species on the surface are suggested by the depth profile of ARXPS spectra. The thickness of the oxidized species, including NiO, Ni(OH)2, Fe2O3, and Fe3O4, are also estimated based on the ARXPS results. This work provides an effective approach to clarify the surface composition, as well as the thickness of the oxide layer of the thin films. [ABSTRACT FROM AUTHOR]

The metallic magnetic thin films are widely used in high-frequency magnetic devices, the reliability of which greatly depends on the saturation magnetization (M s) and resonance frequency (f r) of the films. However, increasing the operating frequency of the magnetic thin film is extremely challenging. This study investigates the microstructure, magnetic domains and magnetic properties of obliquely deposited Ti/Fe/Ni 81 Fe 19 /Fe/Ti multilayer films. The coercivity distribution of the deposited films is investigated by first order reversal curve (FORC) measurements. The result of static magnetic properties revealed the in-plane uniaxial anisotropy with a high anisotropy field (H k) up to 495 Oe. A magneto-optical Kerr microscope image displayed the multi-step magnetization reversal processes at different oblique angles. Complex permeability spectra indicated that the resonance frequency increases from 1.27 to 4.71 GHz as the deposition angle is increased from 0° to 25°. Thus, Ti/Fe/Ni 81 Fe 19 /Fe/Ti multilayer film with tunable magnetic performances is one of the good candidate materials for microwave devices. • This study investigates the microstructure, magnetic domains and magnetic properties of Ti/Fe/Ni 81 Fe 19 /Fe/Ti films. • The self-shadowing effect is observed in the films deposited at 15°, which showed an obvious columnar structure. • The dynamic magnetic properties show that the oblique deposition angle can tune the f r of samples from 1.27 to 4.71 GHz. [ABSTRACT FROM AUTHOR]

• Oblique deposition can vary surface morphology of NiFe films. • Large inclination angle produce strongly magnetic anisotropy of NiFe films. • Oblique deposition plays a significant role in tuning resonance frequency of magnetic films. The soft magnetic metal films own potential applications for high frequency magnetic devices. The operating frequency and reliability of the devices depend on the saturation magnetization and resonance frequency of metal films. Increasing the application frequency of the magnetic thin film is extremely challenging. Herein, we deposited a series of NiFe films using electron beam evaporation with various inclination angles, and investigated the surface morphology and magnetic properties, respectively. This paper presents the relationship between surface morphology and inclination angle. [ABSTRACT FROM AUTHOR]

• Static magnetic and microwave properties of Fe/NiFe/Fe films are regulated by Fe thickness. • The strong pinning effect has been found when the thickness of Fe reaches 4 nm. • The value of the exchange stiffness is obtained by fitting the PSSW mode. Microwave devices, designed by the electromagnetic characteristics of spin waves, are widely used in radio frequency circuits and microwave systems, such as magnetic tunable filters, frequency multiplier, and signal-to-noise ratio enhancers. In order to manufacture these devices, it is not only the saturation magnetization (4π M s) and ferromagnetic resonance linewidth (Δ H) that need to be regulated, but also the exchange stiffness (A). In this study, the Fe (t nm)/Ni 81 Fe 19 (50 nm)/Fe (t nm) multilayer films were proposed to regulate the 4π M s , Δ H , and A , which were fabricated using electron beam evaporation, and the dynamic magnetic properties of the film were studied by ferromagnetic resonance (FMR) spectroscopy. Firstly, we obtain the 4π M s , γ and H a by fitting the uniform FMR mode. Then we obtain the exchange stiffness by fitting the first (p = 1) perpendicular standing spin wave (PSSW) mode. With the increasing Fe film thickness, the calculated saturation magnetization increased from 9250 to 14060Gs, FMR linewidth increased from 111.5 to 140.3Oe and the exchange stiffness decreased from 22.1 × 10−12 to 7.8 × 10−12J/m. [ABSTRACT FROM AUTHOR]