Perpendicular Standing Spin Wave and Magnetic Anisotropic Study on Amorphous FeTaC Films

Samantaray, B.; Singh, A. K.; Banerjee, Chandrima; Barman, Anjan; Perumal, A.; Mandal, P.

doi:10.1109/tmag.2016.2520981

Cited by 9 publications

(6 citation statements)

References 17 publications

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“…However, at thicknesses greater than 55 nm, 𝐴 𝑒𝑥,𝑎𝑝𝑝 shows a monotonic increase. Similar variations have been reported by Belmeguenai et al [38], although this was attributed to a lack of precision in their work, and by Samantaray [33].…”

Section: Figsupporting

confidence: 88%

Exchange stiffness constant determination using multiple-mode FMR perpendicular standing spin waves

Waring

Johansson

et al. 2023

Journal of Applied Physics

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The exchange stiffness constant is recognized as one of the fundamental properties of magnetic materials, though its accurate experimental determination remains a particular challenge. In thin films, resonance measurements exploiting perpendicular standing spin waves (PSSWs) are increasingly used to extract this parameter, typically through a determination of the first-order PSSW mode. Here, we present a systematic study of multiple PSSW modes in NiFe films, where both the sample thickness and the cap layer material are varied. The results show that a simple analysis based on the Kittel rigid pinning model yields an exchange stiffness constant that varies with thickness, mode number, and capping layer material. This finding is clearly inconsistent with physical expectation that the exchange stiffness constant of a material is single valued for a particular set of thermodynamic conditions. Using a more general exchange boundary condition, we show, through a comprehensive set of micromagnetic simulations, that a dynamic pinning mechanism originally proposed by Wigen is able to reproduce the experimental results using a single value of Aex. Our findings support the utility of short wavelength, higher order PSSWs to determine the Aex of thin films and show that the value of Aex obtained has a weak dependency on the material immediately adjacent to the magnetic layer.

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Section: Figsupporting

confidence: 88%

Exchange stiffness constant determination using multiple-mode FMR perpendicular standing spin waves

Waring

Johansson

et al. 2023

Journal of Applied Physics

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“…The secondary mode has fingerprints of a perpendicular standing spin wave (PSSW) mode [56,57]. For the films with thicknesses of 100 and 150 nm (the latter not shown here), which still present in-plane uniaxial magnetic anisotropy, the secondary resonance mode may be associated to non-homogeneous magnetization configuration and some dispersion of the magnetic anisotropy.…”

Section: Dynamic Magnetic Responsementioning

confidence: 80%

“…For the films with thicknesses above 200 nm, presenting isotropic in-plane magnetic properties and outof-plane magnetic anisotropy contribution, the secondary resonance mode in turn is a response of regions with local anisotropies originated from the non-uniformity of the stress [6]. In particular, similar FMR spectra are characteristic of systems with non-homogeneous magnetization configuration [15,54,56,57].…”

Section: Dynamic Magnetic Responsementioning

confidence: 99%

Thickness dependence of the magnetic anisotropy and dynamic magnetic response of ferromagnetic NiFe films

Silva

Corrêa

Pace

et al. 2017

J. Phys. D: Appl. Phys.

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We investigate the thickness dependence of the magnetic anisotropy and dynamic magnetic response of ferromagnetic NiFe films. We go beyond quasi-static measurements and focus on the dynamic magnetic response by considering three complementary techniques: the ferromagnetic resonance, magnetoimpedance and magnetic permeability measurements. We verify remarkable modifications in the magnetic anisotropy, i.e. the well-known behavior of in-plane uniaxial magnetic anisotropy systems gives place to a complex magnetic behavior as the thickness increases, and splits the films in two groups according to the magnetic properties. We identify magnetoimpedance and magnetic permeability curves with multiple resonance peaks, as well as the evolution of the ferromagnetic resonance absorption spectra, as fingerprints of strong changes of the magnetic properties associated to the vanishing of the in-plane magnetic anisotropy and to the emergence of non-homogeneous magnetization configuration, local anisotropies and out-of-plane anisotropy contribution arisen as a consequence of the non-uniformities of the stress stored in the film as the thickness is increased and/or to the columnar growth of the film. We interpret the experimental results in terms of the structural and morphological properties, quasi-static magnetic behavior, magnetic domain structure and different mechanisms governing the magnetization dynamics at distinct frequency ranges.

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“…Both resonance fields H r and linewidths ΔH increase markedly from the easy axis to the hard axis. In addition, for easy axis [110] direction, it is notable that an additional resonance mode, i.e., perpendicular standing spin wave (PSSW) mode, [42][43][44] was excited at a lower resonance field, [42,45] which may be attributed to the surface partial spin pinning affected by anisotropy field. [45][46][47] Figure 3c,d shows the frequency and angular dependence of the resonance field H r .…”

Section: Angular Dependence Of Gilbert Damping In Co 14 Fe 16 Al Filmmentioning

confidence: 99%

“…In addition, for easy axis [110] direction, it is notable that an additional resonance mode, i.e., perpendicular standing spin wave (PSSW) mode, [42][43][44] was excited at a lower resonance field, [42,45] which may be attributed to the surface partial spin pinning affected by anisotropy field. [45][46][47] Figure 3c,d shows the frequency and angular dependence of the resonance field H r . To quantify the magnetocrystalline anisotropy, H r is fitted using the Kittel equation [48,49]…”

Section: Angular Dependence Of Gilbert Damping In Co 14 Fe 16 Al Filmmentioning

confidence: 99%

Colossal Gilbert Damping Anisotropy in Heusler‐Alloy Thin Films

Wang

et al. 2023

Adv Elect Materials

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Hence, it is crucial to manipulate the Gilbert damping on demand for versatile spintronic applications. Extensive efforts have been made including material optimization, [7][8][9][10][11] interface engineering, [12][13][14][15] spin torque, [16][17] and damping anisotropy. [18][19][20][21] Among these approaches, utilizing intrinsic Gilbert damping anisotropy, without requiring multiple magnetic devices or large critical current density, has attracted considerable attention. Such a method allows continuous damping manipulation via rotating the magnetization direction.Heusler compounds constitute a prominent class of magnetic materials featuring high spin polarization [22][23][24] and ultralow magnetic damping [25][26] in spintronics. Although many theoretical works [27][28][29] predict the existence of Gilbert damping anisotropy, there has been a lack of strong experimental evidence in Heusler alloys. For instance, the earlier works, such as Co 2 FeSi, [30] Co 2 MnSi, [31] and Co 2 FeAl, [25,32,33] did not provide any convincing analysis of the intrinsic damping anisotropy. At the same time, those reported effects [30][31][32][33] are too weak to develop novel functionality in spintronic devices. Hence, seeking new Heusler ingredients with significant Gilbert damping anisotropy has become a tremendous challenge. Additionally, the key mechanism behind this effect remains unexplored in Heusler alloys.In this work, we have deposited the Heusler-alloy Co 3−x Fe x Al (x = 1-2) single crystalline thin films using the molecular beam epitaxy (MBE) technique. The in-plane angular dependent ferromagnetic resonance (FMR) measurements show that the anisotropic damping exhibits fourfold symmetry and the maximal ratio of up to 1400% for the optimized sample Co 1.4 Fe 1.6 Al, which is nearly three times higher than the highest value of 420% reported in metallic ferromagnets. [34] Furthermore, according to anisotropic magnetoresistance (AMR) measurement and first-principles calculation, we ascribed such colossal anisotropy of Gilbert damping to the variation of the spin-orbit coupling (SOC). Our results help explore the larger anisotropic damping ratio in Heusler alloys and understand its mechanism for spintronic applications. Results and Discussion Anisotropic Magnetization Relaxation of Co 3−x Fe x Al FilmsHeusler alloy Co 3−x Fe x Al (x = 1-2) thin films were grown on the MgO (001) substrates by MBE. The details of structural characteristics Manipulating Gilbert damping is of critical importance in spintronic devices. Here, this work reports the damping anisotropy of Heusler-alloy Co 3−x Fe x Al single crystalline thin films using inductive ferromagnetic resonance. A colossal Gilbert damping anisotropy ratio of up to 1400%, nearly three times higher than the highest value reported among known metallic ferromagnets, is observed in the optimized sample Co 1.4 Fe 1.6 Al. The Gilbert damping anisotropy with strong fourfold symmetry is attributed to the variation of the spin-orbit coupling, which is further corroborated by the cur...

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Perpendicular Standing Spin Wave and Magnetic Anisotropic Study on Amorphous FeTaC Films

Cited by 9 publications

References 17 publications

Exchange stiffness constant determination using multiple-mode FMR perpendicular standing spin waves

Exchange stiffness constant determination using multiple-mode FMR perpendicular standing spin waves

Thickness dependence of the magnetic anisotropy and dynamic magnetic response of ferromagnetic NiFe films

Colossal Gilbert Damping Anisotropy in Heusler‐Alloy Thin Films

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