Ultrafast magnetization dynamics rates within the Landau-Lifshitz-Bloch model

Atxitia, Unai; Chubykalo‐Fesenko, O.

doi:10.1103/physrevb.84.144414

Cited by 108 publications

(107 citation statements)

References 61 publications

Supporting

Mentioning

100

Contrasting

Order By: Relevance

“…It was shown that the M3TM and LLB models are equal in the description of the heat-triggered, longitudinal spin-dynamics. 130 In certain limits, both can be solved analytically, and novel scenarios can be developed within these frameworks.…”

Section: Theoretical Perspectivesmentioning

confidence: 99%

Perspective: Ultrafast magnetism and THz spintronics

Walowski

Münzenberg

2016

Journal of Applied Physics

336

205

View full text Add to dashboard Cite

This year the discovery of femtosecond demagnetization by laser pulses is 20 years old. For the first time, this milestone work by Bigot and coworkers gave insight directly into the time scales of microscopic interactions that connect the spin and electron system. While intense discussions in the field were fueled by the complexity of the processes in the past, it now became evident that it is a puzzle of many different parts. Rather than providing an overview that has been presented in previous reviews on ultrafast processes in ferromagnets, this perspective will show that with our current depth of knowledge the first applications are developed: THz spintronics and all-optical spin manipulation are becoming more and more feasible. The aim of this perspective is to point out where we can connect the different puzzle pieces of understanding gathered over 20 years to develop novel applications. Based on many observations in a large number of experiments. Differences in the theoretical models arise from the localized and delocalized nature of ferromagnetism. Transport effects are intrinsically non-local in spintronic devices and at interfaces. We review the need for multiscale modeling to address the processes starting from electronic excitation of the spin system on the picometer length scale and sub-femtosecond time scale, to spin wave generation, and towards the modeling of ultrafast phase transitions that altogether determine the response time of the ferromagnetic system. Today, our current understanding gives rise to the first usage of ultrafast spin physics for ultrafast magnetism control: THz spintronic devices. This makes the field of ultrafast spin-dynamics an emerging topic open for many researchers right now. Published by AIP Publishing. [http://dx

show abstract

Section: Theoretical Perspectivesmentioning

confidence: 99%

Perspective: Ultrafast magnetism and THz spintronics

Walowski

Münzenberg

2016

Journal of Applied Physics

336

205

View full text Add to dashboard Cite

show abstract

“…Within the LLB model a similar estimate can been found. 13 In particular, for ferromagnets, the relaxation time has been shown to be defined as τ ∼ χ (T )/λ, where χ = (∂m/∂H) H→∞ is the longitudinal susceptibility and m is the thermally averaged spin polarization. This depends on: (i) the particular dissipation mechanism represented by the coupling parameter λ, and (ii) the longitudinal susceptibility χ (T ).…”

Section: Estimation Of the Temperature Dependent Magnetization Relmentioning

confidence: 99%

“…13,[37][38][39][40][41][42] In ferrimagnets, there is a large interest on demagnetization rates of each species, following the use of X-ray magnetic circular dichroism 5 to monitor the sub-picosecond dynamics of each sublattice magnetization individually. 4 Thermal effects dominate the magnetization dynamics during the heating produced by the laser.…”

Section: Estimation Of the Temperature Dependent Magnetization Relmentioning

confidence: 99%

“…More sophisticated approaches such as the LandauLifshitz-Bloch (LLB) 13,18 and microscopic three temperature model (M3TM) 14 models take into account the spin exchange interactions within the mean field approximation. The M3TM model also within the MFA (Weiss) shows that the timescale is essentially defined by µ 0 /T c .…”

Section: Estimation Of the Temperature Dependent Magnetization Relmentioning

confidence: 99%

“…In pure ferromagnets the ratio between the magnetic moment and the Curie temperature, µ 0 /T c (or more precisely 13 µ 0 /λT c ) has been shown to be a good approximation of the speed of demagnetization, allowing one to classify ferromagnetic materials into two types, fast and slow. 14 Using this simplistic argument in TM-RE alloys such as TbFe, 6 TbCo, 15 or GdFeCo 2 and assuming a shared T c , 16 transition metal demagnetization times are approximately µ RE /µ TM ≈ 4 − 5 times faster than those of the rare earth.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Controlling the polarity of the transient ferromagneticlike state in ferrimagnets

et al. 2014

Self Cite

View full text Add to dashboard Cite

It was recently observed that the two antiferromagnetically coupled sublattices of a rare earth-transition metal ferrimagnet can temporarily align ferromagnetically during femtosecond laser heating, but always with the transition metal aligning in the rare earth direction. This behavior has been attributed to the slower magnetization dynamics of the rare earth sublattice. The aim of this work was to assess how the difference in the speed of the transition metal and rare earth dynamics affects the formation of the transient ferromagnetic-like state and consequently controls its formation. Our investigation was performed using extensive atomistic spin simulations and analytic micromagnetic theory of ferrimagnets, with analysis of a large area of parameter space such as initial temperature, Gd concentration and laser fluence. Surprisingly, we found that at high temperatures, close to the Curie point, the rare earth dynamics become faster than those of the transition metal. Subsequently we show that the transient state can be formed with the opposite polarity, where the rare earth aligns in the transition metal direction. Our findings shed light on the complex behavior of this class of ferrimagnetic materials and highlight an important feature which must be considered, or even exploited, if these materials are to be used in ultrafast magnetic devices.

show abstract

Engineering Co₂MnAl_xSi₁₋_x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization

et al. 2020

View full text Add to dashboard Cite

Engineering of magnetic materials for developing better spintronic applications relies on the control of two key parameters: the spin polarization and the Gilbert damping, responsible for the spin angular momentum dissipation. Both of them are expected to affect the ultrafast magnetization dynamics occurring on the femtosecond timescale. Here, engineered Co2MnAlxSi1‐x Heusler compounds are used to adjust the degree of spin polarization at the Fermi energy, P, from 60% to 100% and to investigate how they correlate with the damping. It is experimentally demonstrated that the damping decreases when increasing the spin polarization from 1.1 × 10−3 for Co2MnAl with 63% spin polarization to an ultralow value of 4.6 × 10−4 for the half‐metallic ferromagnet Co2MnSi. This allows the investigation of the relation between these two parameters and the ultrafast demagnetization time characterizing the loss of magnetization occurring after femtosecond laser pulse excitation. The demagnetization time is observed to be inversely proportional to 1 – P and, as a consequence, to the magnetic damping, which can be attributed to the similarity of the spin angular momentum dissipation processes responsible for these two effects. Altogether, the high‐quality Heusler compounds allow control over the band structure and therefore the channel for spin angular momentum dissipation.

show abstract

Ultrafast magnetization dynamics rates within the Landau-Lifshitz-Bloch model

Cited by 108 publications

References 61 publications

Perspective: Ultrafast magnetism and THz spintronics

Perspective: Ultrafast magnetism and THz spintronics

Controlling the polarity of the transient ferromagneticlike state in ferrimagnets

Engineering Co₂MnAl_xSi₁₋_x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization

Contact Info

Product

Resources

About

Ultrafast magnetization dynamics rates within the Landau-Lifshitz-Bloch model

Cited by 108 publications

References 61 publications

Perspective: Ultrafast magnetism and THz spintronics

Perspective: Ultrafast magnetism and THz spintronics

Controlling the polarity of the transient ferromagneticlike state in ferrimagnets

Engineering Co2MnAlxSi1−x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization

Contact Info

Product

Resources

About

Engineering Co₂MnAl_xSi₁₋_x Heusler Compounds as a Model System to Correlate Spin Polarization, Intrinsic Gilbert Damping, and Ultrafast Demagnetization