Correlation Between Ultrafast Demagnetization Process and Gilbert Damping in Amorphous TbFeCo Films

Ren, Yang; Zuo, YL; S., M.; Zhang, Z. Z.; Zhou, Shiming

doi:10.1109/tmag.2013.2239269

Cited by 26 publications

(15 citation statements)

References 15 publications

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“…L M M and   is the component of the magnetic susceptibility perpendicular to the external magnetic field. We assume the effective Gilbert damping constant, which is a function of the composition and temperature [49], to be equal to 0.2. An example of the calculated dynamics can be found in Fig.…”

Section: Ultrafast Magnetism and Critical Slowdown In High Magnetic F...mentioning

confidence: 99%

High-field anomalies of equilibrium and ultrafast magnetism in rare-earth–transition-metal ferrimagnets

et al. 2019

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Magneto-optical spectroscopy in fields up to 30 Tesla reveals anomalies in the equilibrium and ultrafast magnetic properties of the ferrimagnetic rare-earth-transition metal alloy TbFeCo. In particular, in the vicinity of the magnetization compensation temperature, each of the magnetizations of the antiferromagnetically coupled Tb and FeCo sublattices show triple hysteresis loops. Contrary to state-of-the-art theory, which explains such loops by sample inhomogeneities, here we show that they are an intrinsic property of the rare-earth ferrimagnets. Assuming that the rare-earth ions are paramagnetic and have a non-zero orbital momentum in the ground state and, therefore, a large magnetic anisotropy, we are able to reproduce the experimentally observed behavior in equilibrium. The same theory is also able to describe the experimentally observed critical slowdown of the spin dynamics in the vicinity of the magnetization compensation temperature, emphasizing the role played by the orbital momentum in static and ultrafast magnetism of ferrimagnets.

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Section: Ultrafast Magnetism and Critical Slowdown In High Magnetic F...mentioning

confidence: 99%

High-field anomalies of equilibrium and ultrafast magnetism in rare-earth–transition-metal ferrimagnets

et al. 2019

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“…By taking into account the discussions above, we suggest that the damping of the present Ni 0.5 Zn 0.5 Fe 2 O 4 powder/polymer composite sheet could be largely related to the 3 d electrons from Fe and Ni atoms. Although further detailed studies are necessary, intuitive considerations would be possible; the coupling between 3 d electrons, 3 d spins, and phonons is sufficiently strong to induce high values 38 in the present Ni 0.5 Zn 0.5 Fe 2 O 4 powder/polymer composite sheet. In the epitaxially-grown spinel structured MgFe 2 O 4 thin film deposited on MgAl 2 O 4 (100) substrate, the value was reported to be approximately 49 .…”

Section: Resultsmentioning

confidence: 99%

“…A magnetic-based material exhibiting a high value implies that the FMR phenomenon of the sample is complicated 38 . In the case of spinel-structured ferrite films, the constituent of cations 39 and high density of crystal defects generated by dislocations and/or antiphase boundaries 40 − 42 affect the damping.…”

Section: Resultsmentioning

confidence: 99%

Dynamical magnetic behavior of anisotropic spinel-structured ferrite for GHz technologies

Yasukawa

Nozawa

Tiittanen

et al. 2021

Sci Rep

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We have fabricated a high quality magnetic Ni0.5Zn0.5Fe2O4 ferrite powder/polymer composite sheet consisting of common and environmentally friendly elements only. The sheet was then tested for its dynamic permeability by irradiating with electromagnetic waves with frequencies up to 50 GHz. Two different originally developed methods were used for the high-frequency permeability measurements, a short-circuited microstrip line method and a microstrip line-probe method. It is challenging to measure the dynamic permeability of magnetic thin films/sheets beyond 10 GHz because of the low response signal from these materials. However, the two methods produced essentially equivalent results. In the frequency dependent permeability profile, the maximum position of the profile, $$\mu ^{\prime \prime }_{max}$$ μ max ″ , shifted towards higher frequencies upon increasing an applied (strong) static external magnetic field, $$H_{dc}$$ H dc . A linear relationship between $$\mu^ {\prime \prime }_{max}$$ μ max ″ and $$H_{dc}$$ H dc for the entire range of $$H_{dc}$$ H dc was observed even at small $$H_{dc}$$ H dc . In general, the spinel-structured Ni-based ferrites exhibit low magnetic anisotropy, but the present sample showed a uniaxial-anisotropic behavior in the parallel direction of the sheet. Our Ni0.5Zn0.5Fe2O4 powder/polymer composite sheet thus exhibits high performance at GHz frequencies, and should be applicable e.g. as an anisotropic electromagnetic wave-interference material.

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“…Unfortunately, measurements of the magnetic damping parameter in polycrystalline Tb0.3Dy0.7Fe2 do not appear to be available in the literature. However, some results on the amorphous Tbx[FeCo]1-x system, achieved by using recent ultra-fast demagnetization techniques, have extracted ~0.5  for compositions (x ~ 0.3) that have high magnetostriction 28 . We can also estimate the scale for the Gilbert damping by using a formalism that takes into account direct magnon to long wavelength phonon conversion via the magnetoelastic interaction and subsequent phonon relaxation to the thermal phonon bath 29 .…”

Section:  mentioning

confidence: 99%

A critical analysis of the feasibility of pure strain-actuated giant magnetostrictive nanoscale memories

Gowtham

Rowlands

Buhrman

2015

Journal of Applied Physics

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Concepts for memories based on the manipulation of giant magnetostrictive nanomagnets by stress pulses have garnered recent attention due to their potential for ultra-low energy operation in the high storage density limit. Here we discuss the feasibility of making such memories in light of the fact that the Gilbert damping of such materials is typically quite high.We report the results of numerical simulations for several classes of toggle precessional and nontoggle dissipative magnetoelastic switching modes. Material candidates for each of the several classes are analyzed and forms for the anisotropy energy density and ranges of material parameters appropriate for each material class are employed. Our study indicates that the Gilbert damping as well as the anisotropy and demagnetization energies are all crucial for determining the feasibility of magnetoelastic toggle-mode precessional switching schemes. The roles of thermal stability and thermal fluctuations for stress-pulse switching of giant magnetostrictive nanomagnets are also discussed in detail and are shown to be important in the viability, design, and footprint of magnetostrictive switching schemes.

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Correlation Between Ultrafast Demagnetization Process and Gilbert Damping in Amorphous TbFeCo Films

Cited by 26 publications

References 15 publications

High-field anomalies of equilibrium and ultrafast magnetism in rare-earth–transition-metal ferrimagnets

High-field anomalies of equilibrium and ultrafast magnetism in rare-earth–transition-metal ferrimagnets

Dynamical magnetic behavior of anisotropic spinel-structured ferrite for GHz technologies

A critical analysis of the feasibility of pure strain-actuated giant magnetostrictive nanoscale memories

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