Ultrafast transient dynamics in composite multiferroics

We uncover and identify the regime for a magnetically and ferroelectrically controllable negative refraction of light traversing multiferroic, oxide-based metastructure consisting of alternating nanoscopic ferroelectric (SrTiO2) and ferromagnetic (Y3Fe2(FeO4)3, YIG) layers. We perform analytical and numerical simulations based on discretized, coupled equations for the self-consistent Maxwell/ferroelectric/ferromagnetic dynamics and obtain a biquadratic relation for the refractive index. Various scenarios of ordinary and negative refraction in different frequency ranges are analyzed and quantified by simple analytical formula that are confirmed by full-fledge numerical simulations. Electromagnetic-waves injected at the edges of the sample are propagated exactly numerically. We discovered that for particular GHz frequencies, waves with different polarizations are characterized by different signs of the refractive index giving rise to novel types of phenomena such as a positive-negative birefringence effect, and magnetically controlled light trapping and accelerations.

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“…(1), along the lines as done in Refs. [21,22]. Furthermore, to access a higher frequency regime (cf.…”

Section: Resultsmentioning

confidence: 99%

Positive–Negative Birefringence in Multiferroic Layered Metasurfaces

et al. 2016

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“…There are several pathways by which an ultrafast optical stimulus may alter the state of a composite multiferroic. One of them relies on ultrafast direct optical control of the magnetization [30] and, via FM-FE coupling, of the ferroelectric polarization [31,32]. Alternatively, ultrafast optically driven changes of the FE state could lead to high-amplitude dynamic strain modulations [33] and, thus, alter the magnetization state of a magnetostrictive layer.…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co40Fe40B20/BaTiO

et al. 2020

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Using a magneto-optical pump-probe technique with micrometer spatial resolution, we show that magnetization precession can be launched in individual magnetic domains imprinted in a Co 40 Fe 40 B 20 layer by elastic coupling to ferroelectric domains in a BaTiO 3 substrate. The dependence of the precession parameters on the strength and orientation of the external magnetic field reveals that laser-induced ultrafast partial quenching of the magnetoelastic coupling parameter of Co 40 Fe 40 B 20 by approximately 27% along with 10% ultrafast demagnetization triggers the magnetization precession. The relation between the laser-induced reduction of the magnetoelastic coupling and the demagnetization is approximated by an n(n + 1)/2 law with n ≈ 2. This correspondence confirms the thermal origin of the laser-induced anisotropy change. Based on analysis and modeling of the excited precession, we find signatures of laser-induced precessional switching, which occurs when the magnetic field is applied along the hard magnetization axis and its value is close to the effective magnetoelastic anisotropy field. The precessionexcitation process in an individual magnetoelastic domain is found to be unaffected by neighboring domains. This makes laser-induced changes of magnetoelastic anisotropy a promising tool for driving magnetization dynamics and switching in composite multiferroics with spatial selectivity.

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“…Spatial magnetic contrast can often be gained using the magneto-optical kerr effect 19 , magnetic force microscopy 20 or even using X-ray scattering measurements 21 . Temporal information is also achievable using pump-probe setups 22 or time-resolved x-ray diffraction 16 , 23 (for structural properties). Complex combinations of some of these measurement techniques also allow for time, spatial and even element resolved measurements simultaneously 21 , 24 , though these tend to require advanced experimental facilities.…”

Section: Introductionmentioning

confidence: 99%

A multiscale model of the effect of Ir thickness on the static and dynamic properties of Fe/Ir/Fe films

Cuadrado

Oroszlány

Szunyogh

et al. 2018

Sci Rep

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The complex magnetic properties of Fe/Ir/Fe sandwiches are studied using a hierarchical multi-scale model. The approach uses first principles calculations and thermodynamic models to reveal the equilibrium spinwave, magnetization and dynamic demagnetisation properties. Finite temperature calculations show a complex spinwave dispersion and an initially counter-intuitive, increasing exchange stiffness with temperature (a key quantity for device applications) due to the effects of frustration at the interface, which then decreases due to magnon softening. Finally, the demagnetisation process in these structures is shown to be much slower at the interface as compared with the bulk, a key insight to interpret ultrafast laser-induced demagnetization processes in layered or interface materials.

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Ultrafast transient dynamics in composite multiferroics

Cited by 8 publications

References 68 publications

Positive–Negative Birefringence in Multiferroic Layered Metasurfaces

Positive–Negative Birefringence in Multiferroic Layered Metasurfaces

Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co40Fe40B20/BaTiO

A multiscale model of the effect of Ir thickness on the static and dynamic properties of Fe/Ir/Fe films

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