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The environmental sensitivity maps would be envisaged as an elaborated scheme exchanging knowledge among numerous stakeholders at decision-making and execution levels. Local knowledge, scientific knowledge and public knowledge are required to associate toward the development of environmental sensitivity maps, particularly the identification of shoreline types and its sensitivity; compiling biology, human-use resource information; ranking, prioritising sensitive sites and resources at risk. Especially, the value of local knowledge has been recognised over time and the need for its effective integration into research and development has grown significantly. One of the options to enhance the role of this knowledge should be participatory tools emphasising researchers-facilitation to obtain indigenous perceptions as well as increase environmental sensitivity maps adoption in the planning, regulatory community in islands and coastal areas.

Nanomagnets are widely used to store information in non-volatile spintronic devices. Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport. However, to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics. Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths. Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation. The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian. Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission. [Figure not available: see fulltext.]

We report the anomalous Nernst effect in trilayers containing a thin film of the half-metallic ferromagnetic Heusler alloy Co2Fe0.4Mn0.6Si with perpendicular magnetic anisotropy. The structure is MgO/CFMS/Pd and we have studied the variation of anomalous Hall and Nernst effects as a function of CFMS and Pd thickness. The anomalous Nernst coefficient reaches 0.5 μV/K at room temperature and we have observed a strong dependence of the anomalous Nernst coefficient on the thickness of both layers. Our results indicate that inducing perpendicular magnetic anisotropy in a strongly spin-polarising Heusler alloy such as CFMS is very promising for new thermoelectric devices based on exploiting the anomalous Nernst effect.

The field of magnon spintronics offers a charge current free way of information transportation by using spin waves (SWs). Compared to forward volume spin waves for example, Damon-Eshbach (DE) SWs need a relatively weak external magnetic field which is suitable for small spintronic devices. In this work we study DE SWs in Co 2 MnSi, a half-metallic Heusler alloy with significant potential for magnonics. Thin films have been produced by pulsed laser deposition. Integrated coplanar waveguide (CPW) antennas with different distances between emitter and detection antenna have been prepared on a Co 2 MnSi film. We used a vector network analyzer to measure spin wave reflection and transmission. We observe spin wave propagation up to 100 μm, a new record for half-metallic Heusler thin films.

In this paper, we investigate the characteristics of antenna for propagating-spin-wave-spectroscopy (PSWS) experiment in ferromagnetic thin films. Firstly, we simulate the amplitude and phase distribution of the high-frequency magnetic field around antenna by high frequency structure simulator (HFSS). And then k distribution of the antenna is obtained by fast Fourier transformation (FFT). Furthermore, three kinds of antenna designs, i.e. micro-strip line, coplanar waveguide (CPW), loop, are studied and compared. How the dimension parameter of antenna influence the corresponding high-frequency magnetic field amplitude and k distribution are investigated in details.

The resistance of the Pt bar deposited on the YIG slab was monitored while the magnetic field was ramped through the ferromagnetic resonance with the YIG slab facing a coplanar waveguide resonator excited at 4.3 GHz excitation. The resistance change provides detection of the ferromagnetic resonance with a high signal-to-noise ratio. It is ascribed to a change in the temperature of the Pt bars. The thermal origin of the signal is confirmed by the observation that the signal vanishes when field modulation is applied at frequencies above 6 Hz. The spin pumping effect was vanishingly small, and the anisotropic magnetoresistance of the Pt bar, though quite easily observed, would imply a rectification voltage that is much smaller than the bolometric effect.

Topological quantum materials have stimulated growing attention because they reveal novel aspects of condensed matter physics and point to new opportunities in materials science, in particular for thermoelectrics. Here, we experimentally study thermoelectric effects in ${\mathrm{HfTe}}_{5}$, which was predicted to be at the boundary between strong and weak topological insulators. The magnetic field dependence of ${\mathrm{HfTe}}_{5}$ thermoelectric properties attests to the anomalous character of this material, supported by our angle-resolved photoemission spectroscopy (ARPES) measurements. At 36 K, the thermopower of $\ensuremath{-}277\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ is reached when a field of 0.4 Tesla is applied, while it is $\ensuremath{-}157\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ at zero field and a large Nernst coefficient up to $600\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ is observed at 100 K with magnetic field of 4 T. A possible topologically nontrivial band structure is proposed to account for our observations. Our results constitute a highly constraining set of data for any model of transport based on ${\mathrm{HfTe}}_{5}$ band structure. Furthermore, the extraordinary thermoelectric properties suggest a new paradigm for the development of thermoelectric applications based on layered transition-metal chalcogenides.

Iron garnets as an important type of low-damping magnetic insulator can provide an ideal platform for the field of magnonics. In this work, we study the propagation of spin waves in a 60 nm-thick TmIG film with perpendicular magnetic anisotropy using all-electrical spin wave spectroscopy. The magnetostatic forward volume mode spin waves show a fully reciprocal propagation. By sweeping out-of-plane magnetic fields in the low-field regime, spin textures are created and observed; meanwhile, the spin wave mode vanishes, which indicates that propagating spin waves are filtered by the spin textures. By applying a large in-plane field, spin wave propagation in a Damon–Eshbach configuration is studied. Our findings provide a potential method to explore reconfigurable magnonic devices.

Anomalous Hall and anomalous Nernst properties of thin MgO/Co2 Fe 0.4 Mn 0.6Si/Pd stacks with perpendicular magnetic anisotropy (PMA) revealed the presence of the magnetic proximity effect (MPE) in the Pd layer. The MPE is evidenced by nanometer range thickness-dependent transport measurements. A three-layer model that combines bulk and interface contributions accounts for our experimental data and provides quantitative estimates for the contributions to the total anomalous Nernst voltage of the ferromagnet Heusler [ + 0.97 μV/(K nm)] and the proximity-magnetized Pd layers [ − 0.17 μV/(K nm)]. The anomalous Nernst effect (ANE) reverses its sign by tuning the thickness of the Heusler layer, which is useful for designing ANE thermopiles.

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In this work, we experimentally evidence the interfacial DMI in a 7-nm-thick YIG film by measuring the nonreciprocal spin-wave propagation in terms of frequency, amplitude, and most importantly group velocities using all electrical spin-wave spectroscopy. The velocities of propagating spin waves show chirality among three vectors, i.e., the film normal direction, applied field, and spin-wave wave vector. By measuring the asymmetric group velocities, we extract a DMI constant of $16\text{ }\text{ }\ensuremath{\mu}\mathrm{J}/{\mathrm{m}}^{2}$, which we independently confirm by Brillouin light scattering. Thickness-dependent measurements reveal that the DMI originates from the oxide interface between the YIG and garnet substrate. The interfacial DMI discovered in the ultrathin YIG films is of key importance for functional chiral magnonics as ultralow spin-wave damping can be achieved.

Magnon spintronics is a prosperous field that promises beyond-CMOS technology based on elementary excitations of the magnetic order that act as information carriers for future computational architectures. Unidirectional propagation of spin waves is key to the realization of magnonic logic devices. However, previous efforts to enhance the magnetostatic surface spin wave nonreciprocity did not realize (let alone control) purely unidirectional propagation. Here we experimentally demonstrate excitation of unidirectional exchange spin waves by a nanoscale magnetic grating consisting of Co nanowires fabricated on an ultrathin yttrium iron garnet film. We explain and model the nearly perfect unidirectional excitation by the chirality of the magneto-dipolar interactions between the Kittel mode of the nanowires and the exchange spin waves of the film. Reversal of the magnetic configurations of film and nanowire array from parallel to antiparallel changes the direction of the excited spin waves. Our results raise the prospect of a chiral magnonic logic without the need to involve fragile surface states.

The thermoelectric and transport properties of MgO/Co2MnGa/Pd stacks with perpendicular magnetic anisotropy were measured. For a nominal 3.3 nm Co2MnGa thickness, the anomalous Nernst coefficient and the Nernst angle at room temperature were found to be 0.3 ± 0.05 μV/K and 5 ± 1 % , respectively. The Nernst and Hall angle temperature dependences show similar trends. Increasing the Co2MnGa thickness to 3.6 nm enhances the anomalous Nernst angle to 6.5% at room temperature. At remanence, the anomalous Nernst coefficient at room temperature is half the saturation value.

Spin waves may constitute key components of low-power spintronic devices. Antiferromagnetic-type spin waves are innately high-speed, stable and dual-polarized. So far, it has remained challenging to excite and manipulate antiferromagnetic-type propagating spin waves. Here, we investigate spin waves in periodic 100-nm-wide stripe domains with alternating upward and downward magnetization in La0.67Sr0.33MnO3 thin films. In addition to ordinary low-frequency modes, a high-frequency mode around 10 GHz is observed and propagates along the stripe domains with a spin-wave dispersion different from the low-frequency mode. Based on a theoretical model that considers two oppositely oriented coupled domains, this high-frequency mode is accounted for as an effective antiferromagnetic spin-wave mode. The spin waves exhibit group velocities of 2.6 km s−1 and propagate even at zero magnetic bias field. An electric current pulse with a density of only 105 A cm−2 can controllably modify the orientation of the stripe domains, which opens up perspectives for reconfigurable magnonic devices. Current pulses of 105 A cm−2 can control the orientation of 100-nm-wide stripe domains in La0.67Sr0.33MnO3 and spin waves of 10 GHz can propagate along these domains with a group velocity of 2.6 km s−1.

The cobalt-based Heusler alloys are promising for spintronic applications, thanks to their high spin polarization and half-metallic character. This work investigates the spin-dependent transport and thermoelectric effects in epitaxial Co${}_{2}$TiSn thin films, with and without V doping. The anomalous Nernst angle and anomalous Hall angle are both determined, and the relationship between these two important parameters is discussed. These experimental results are a step toward realizing spin-caloritronic devices for efficient on-chip energy harvesting of waste heat.

Yttrium iron garnet (YIG) has been widely used in spin wave studies thanks to its low Gilbert damping constant. However, most high-quality YIG films are grown on gadolinium gallium garnet (GGG) substrate, which makes it difficult to integrate with existing semiconductor technology. We show spin wave excitation in a nanometer-thick YIG micro-channel on silicon substrate. The YIG is grown by pulsed laser deposition (PLD) in high-purity oxygen followed by rapid thermal annealing at 800 degrees C after deposition. Using meander coplanar waveguides at submicrometer scale, spin waves with wavelength down to 1 mu m are excited. By measuring the linewidth of the spin wave reflection spectra, a Gilbert damping constant alpha = 1.9 x 10(-3) was obtained.

Recent years have witnessed a rapidly growing interest in exploring the use of spin waves for information transmission and computation toward establishing a spin-wave-based technology that is not only significantly more energy efficient than the CMOS technology, but may also cause a major departure from the von-Neumann architecture by enabling memory-in-logic and logic-in-memory architectures. A major bottleneck of advancing this technology is the excitation of spin waves with short wavelengths, which is a must because the wavelength dictates device scalability. Here, we report the discovery of an approach for the excitation of nm-wavelength spin waves. The demonstration uses ferromagnetic nanowires grown on a 20-nm-thick Y3Fe5O12 film strip. The propagation of spin waves with a wavelength down to 50 nm over a distance of 60,000 nm is measured. The measurements yield a spin-wave group velocity as high as 2600 m s−1, which is faster than both domain wall and skyrmion motions., Short-wavelength spin waves with high group velocity are one of the key ingredients for the spin-wave based memory-logics. Here the authors demonstrate the propagation of spin waves with wavelength down to 50 nm and group velocity up to 2600 m s−1 using ferromagnetic nanowires grown on a thin Y3Fe5O12 film strip structure.

Ferromagnetic Heusler alloys with low magnetic damping are highly promising materials for magnonic devices, which rely on the excitation and detection of spin waves. Using all-electrical spin-wave spectroscopy we report spin-wave propagation in sputtered ${\mathrm{Co}}_{2}({\mathrm{Mn}}_{0.6}{\mathrm{Fe}}_{0.4})\text{Si}$ Heusler alloy thin films with a thickness of 50 nm. We integrated a nanostructured microwave antenna to locally excite and detect propagating spin waves in a Damon-Eshbach configuration. We estimate the group velocity to be up to 12.0 km/s and we observe spin-wave propagation with a frequency band as broad as 15 GHz. From the experimental frequency dependence of group velocity we calculate the spin-wave dispersion. Our results show that all-electrical measurements are a powerful method for determining the fundamental spin-wave characteristics of Heusler alloys, over a broad and tunable range of frequencies, and with group velocities an order of magnitude higher than in conventional materials.

Spin-dependent thermoelectric transport properties have been experimentally studied on a micro-structured device based on epitaxially grown 75-nm-thick Co2Ti0.6V0.4Sn0.75 Heusler film with integrated heater and thermometers. The anomalous Nernst coefficient is found to be 0.5 μV/K at 50 K. Thermoelectric power in both longitudinal and transverse directions have been measured with magnetic field rotated in-plane. Asymmetric peaks and valleys are observed at particular in-plane field angle around 25 K. These anomalous peaks show novel magnetic hysteresis due to the interplay between the magnetization and the temperature gradient. These complex behaviors of thermoelectric effect during magnetization reversal still need to be understood.

Magnetic thin films with perpendicular magnetic anisotropy (PMA) offer opportunities for studying magnetostatic forward volume mode (MSFVM) spin waves with isotropic propagation. Here, we realize the full reciprocal MSFVM spin wave propagation in a 30-nm-thick manganese doped yttrium iron garnet (YIG) with PMA by only applying an external field of 5 mT. The external magnetic field required for investigating the MSFVM spin waves in YIG is reduced by 34 times compared to the in-plane magnetized one. The spin wave group velocity and decay length are also investigated. Our finding paves the way for applications of isotropic magnonic computing systems and logic devices.

The anomalous Nernst effect in a perpendicularly magnetized Ir22Mn78/Co20Fe60B20/MgO thin film is measured using well-defined in-plane temperature gradients. The anomalous Nernst coefficient reaches 1.8 mu V/K at room temperature, which is almost 50 times larger than that of a Ta/Co20Fe60B20/MgO thin film with perpendicular magnetic anisotropy. The anomalous Nernst and anomalous Hall results in different sample structures revealing that the large Nernst coefficient of the Ir22Mn78/Co20Fe60B20/MgO thin film is related to the interface between CoFeB and IrMn. Published by AIP Publishing.

The damping of spin waves transmitted through a two-port magnonic device implemented on a yttrium iron garnet thin film is shown to be proportional to the temperature gradient imposed on the device. The sign of the damping depends on the relative orientation of the magnetic field, the wave vector, and the temperature gradient. The observations are accounted for qualitatively and quantitatively by using an extension of the variational principle that leads to the Landau-Lifshitz equation. All parameters of the model can be obtained by independent measurements.