Approaching soft X-ray wavelengths in nanomagnet-based microwave technology

Yu, Haiming; Kelly, Olivier d'Allivy; Cros, Vincent; Bernard, Rozenn; Bortolotti, Paolo; Anane, A.; Brandl, Florian; Heimbach, Florian; Grundler, D.

doi:10.1038/ncomms11255

Cited by 166 publications

(156 citation statements)

References 35 publications

Supporting

Mentioning

155

Contrasting

Order By: Relevance

“…Alternatives based on wavelength conversions in the vicinity of microwave antennas are also available. Examples include tapered waveguides [14], waveguides coupled to a magnetic antenna [15], grating couplers [16,17], isolated antidots [18,19], and nanowire or nanodisk microwave-to-spin-wave transducers [20,21]. Attaining short-wavelength spin-wave emission with any of these approaches requires patterning of a ferromagnetic layer at the nanoscale.…”

Section: Introductionmentioning

confidence: 99%

“…The wavelength of the emitted spin waves is tunable from a few micrometers to about 100 nm by reorientation of an external bias field. Compared to methods that rely on a modification of the effective magnetic field by nanostructuring [14,[16][17][18][19][20][21], the presented multiferroic system does not require lithography. Finally, we show that dynamic fluctuations of the effective magnetic field at a single-anisotropy boundary suffices for broadband spinwave emission.…”

Section: Introductionmentioning

confidence: 99%

“…With increasing excitation frequency, the character of the emitted spin waves changes from magnetostatic to exchange dominated. Magnetic anisotropy boundaries under global excitation conditions can, thus, be used as tunable sources of spin waves with ultrashort wavelength comparable to soft x rays [21].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tunable Short-Wavelength Spin-Wave Emission and Confinement in Anisotropy-Modulated Multiferroic Heterostructures

Hämäläinen¹,

Brandl

Franke³

et al. 2017

Phys. Rev. Applied

View full text Add to dashboard Cite

We report on the generation and confinement of short-wavelength spin waves in a continuous film with periodically modulated magnetic anisotropy. The concept, which is demonstrated for strain-coupled Co 40 Fe 40 B 20 =BaTiO 3 heterostructures, relies on abrupt rotation of magnetic anisotropy at the boundaries of magnetic stripe domains. In combination with an external bias field, this modulation of magnetic anisotropy produces a lateral variation of the effective magnetic field, leading to local spin-wave excitation when irradiated by a microwave magnetic field. In domains with small effective field, spin waves are perfectly confined by the spin gap in neighboring domains. In contrast, standing spin waves in domains with large effective field radiate into neighboring domains. Using micromagnetic simulation, we show that the wavelength of emitted spin waves is tunable from a few micrometers down to about 100 nm by rotation of the bias field. Importantly, the orientation of the wave front remains fixed. We also demonstrate that dynamic fluctuations of the effective magnetic field produce exchange-dominated spin waves at singleanisotropy boundaries. The multiferroic heterostructures presented here enable the use of global excitation fields from a microwave antenna to emit tunable spin waves from a nanometer-wide line source at welldefined locations of a continuous ferromagnetic film.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tunable Short-Wavelength Spin-Wave Emission and Confinement in Anisotropy-Modulated Multiferroic Heterostructures

Hämäläinen¹,

Brandl

Franke³

et al. 2017

Phys. Rev. Applied

View full text Add to dashboard Cite

show abstract

“…Exchange-dominated spin waves with wavelengths smaller than 100 nm can exhibit large v g in thin YIG as well 43 . Here, f is around 10 GHz or even larger.…”

mentioning

confidence: 99%

“…Further optimized microwave-to-magnon transducers based on e.g. grating couplers 43 , individual nanomagnets 44 , or sample edges 45 will allow one to excite spin waves with small λ and relatively large v g in the exchange-dominated regime. Still, related decay lengths need to be explored.…”

mentioning

confidence: 99%

Spin waves with large decay length and few 100 nm wavelengths in thin yttrium iron garnet grown at the wafer scale

Maendl

Stasinopoulos

Grundler

2017

Applied Physics Letters

View full text Add to dashboard Cite

Using conventional coplanar waveguides (CPWs) we excited spin waves with a wavelength λ down to 310 nm in a 200 nm thin yttrium iron garnet film grown by liquid phase epitaxy. Spin-wave transmission was detected between CPWs that we separated by up to 2 mm. For magnetostatic surface spin waves we found a large nonreciprocity of 0.9 and a high group velocity v g of up to 5.4 km/s. The extracted decay length l d amounted to 0.86 mm. Small λ, high v g and large l d are key figures of merit when aiming at non-charged based signal transmission and logic devices with spin waves.Thin films of the insulating ferrimagnet yttrium iron garnet (YIG) have recently shown to exhibit small spin-wave (SW) damping [1][2][3][4][5][6][7] . A large decay length of up to 0.58 mm was reported for SWs in a 20 nm thick YIG film 3 . In Ref.3 , the films were grown by pulsed laser deposition (PLD) on small substrates of (111) gadolinium gallium garnet (GGG) with a lateral size of about 10 mm × 10 mm. Small damping is important for coherent nanomagnonics, low power consumption and devices such as magnonic holography memory, non-linear cellular networks and SW interferometers 3,[8][9][10][11] . Nonreciprocal characteristics of spin waves further enriches possible logic applications 12 . To scale substrate sizes up, PLD is however very challenging. Here, for instance, magnetron sputtering 13 and liquid phase epitaxy 7,14 are more suitable. Still, for decades, commercially available YIG films grown by liquid phase epitaxy (LPE) had a thickness of 1 µm and beyond 15 . Such thicknesses do not allow for application in nanomagnonics. Recently, a 500 nm thick LPE-grown film was explored with and without nanopatterning 16 . Parameters such as decay length l d , group velocity v g , and nonreciprocity parameter β were however not provided. Note that wafer bonding has already been explored to transfer LPE-grown YIG onto Si substrates to advance integrated photonics 17,18 . Such a route might be interesting for hybrid magnonic devices, and it is timely to explore in detail SW properties of thin YIG grown by LPE.We report on experiments performed on a commercially available YIG film ordered with a thickness t = 200 nm that was grown by LPE on a 3" GGG substrate 20 . Using coplanar waveguides (CPWs) we explored spin-wave propagation over broad frequency and magnetic field regimes. The smallest wavelength λ that we excited by the conventional CPWs amounted to 310 nm. This value is smaller than the wavelengths so far excited via microwave antenna in thin YIG with thicknesses ranging from 20 to 500 nm 3,6,16 . At the same time, we observe modes of higher order compared to earlier publications reporting spin-wave excitation in thin YIG 3,16,21 and thin ferromagnetic metals 22,23 using bare CPWs. The nonreciprocity is found to be pronounced with a parameter β of up to 0.9, much larger compared to 20 nm thick YIG 3 . For magnetostatic surface spin waves (MSSWs) we extract a decay length of 0.86 mm that is a factor of 1.5 larger compared to Ref. [3]. The resul...

show abstract

Direct Observation of Worm‐Like Nanochannels and Emergent Magnon Motifs in Artificial Ferromagnetic Quasicrystals

Watanabe

Bhat

Baumgaertl

et al. 2020

Adv Funct Materials

View full text Add to dashboard Cite

Quasicrystalline structures and aperiodic metamaterials find applications ranging from established consumer gadgets to potential high‐tech photonic components owing to both complex arrangements of constituents and exotic rotational symmetries. Magnonics is an evolving branch of magnetism research where information is transported via magnetization oscillations (magnons). Their control and manipulation are so far best accomplished in periodic metamaterials which exhibit properties artificially modulated on the nanoscale. They give rise to functional components, such as band stop filters, magnonic transistors and nanograting couplers. Here, spin‐wave excitations in artificial ferromagnetic quasicrystals created via aperiodic arrangement of nanoholes are studied experimentally. Their ten‐fold rotational symmetry results in multiplexed magnonic nanochannels, suggesting a width down to 50 nm inside a so‐called Conway worm. Key elements of design are emergent magnon motifs and the worm‐like features which are scale‐invariant and not present in the periodic metamaterials. By imaging wavefronts in quasicrystals, insight is gained into how the discovered features materialize as a dense wavelength division multiplexer.

show abstract

Approaching soft X-ray wavelengths in nanomagnet-based microwave technology

Cited by 166 publications

References 35 publications

Tunable Short-Wavelength Spin-Wave Emission and Confinement in Anisotropy-Modulated Multiferroic Heterostructures

Tunable Short-Wavelength Spin-Wave Emission and Confinement in Anisotropy-Modulated Multiferroic Heterostructures

Spin waves with large decay length and few 100 nm wavelengths in thin yttrium iron garnet grown at the wafer scale

Direct Observation of Worm‐Like Nanochannels and Emergent Magnon Motifs in Artificial Ferromagnetic Quasicrystals

Contact Info

Product

Resources

About