Magnetic properties of amorphous thin films produced by ion mixing

We have produced several magnetic amorphous alloys by ion mixing of thin multilayer films. Our results show that the ion mixing technique is able to produce amorphous films of the various categories (transition metal-metalloid, transition metal pairs) at the composition appropriate for the appearance of magnetic ordering. A comparison of their saturation magnetization with that of related vapor quenched films suggests similar nearest-neighbor coordination in both kinds of samples

Optical properties of gyroid structured materials: from photonic crystals to metamaterials

This is the accepted manuscript. The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/adom.201400333/abstract.The gyroid is a continuous and triply periodic cubic morphology which possesses a constant mean curvature surface across a range of volumetric fill fractions. Found in a variety of natural and synthetic systems which form through self-assembly, from butterfly wing scales to block copolymers, the gyroid also exhibits an inherent chirality not observed in any other similar morphologies. These unique geometrical properties impart to gyroid structured materials a host of interesting optical properties. Depending on the length scale on which the constituent materials are organised, these properties arise from starkly different physical mechanisms (such as a complete photonic band gap for photonic crystals and a greatly depressed plasma frequency for optical metamaterials). This article reviews the theoretical predictions and experimental observations of the optical properties of two fundamental classes of gyroid structured materials: photonic crystals (wavelength scale) and metamaterials (subwavelength scale).This work was supported by the EPSRC through the Cambridge NanoDTC EP/G037221/1, EP/G060649/1, EP/L027151/1, and ERC LINASS 320503

Preferential Oxidation of Fe in Permalloy Films

On the basis of He-ion backscattering, x-ray fluorescence, and complementary measurements, it is unambiguously established for the first time that the oxide layer on the surface of oxidized 81% Ni-19% Fe evaporated films is predominantly Fe-oxide. Extrapolation of results for pure iron films indicates that the oxide is most likely antiferromagnetic alpha-Fe2O3. On the basis of ferromagnetic resonance measurements, it is concluded that the oxide negligibly affects the pinning of the bulk spins at the film-oxide interface

Unique wing scale photonics of male Rajah Brooke's birdwing butterflies

Background: Ultrastructures in butterfly wing scales can take many shapes, resulting in the often striking coloration of many butterflies due to interference of light. The plethora of coloration mechanisms is dazzling, but often only single mechanisms are described for specific animals. Results: We have here investigated the male Rajah Brooke's birdwing, Trogonoptera brookiana, a large butterfly from Malaysia, which is marked by striking, colorful wing patterns. The dorsal side is decorated with large, iridescent green patterning, while the ventral side of the wings is primarily brown-black with small white, blue and green patches on the hindwings. Dense arrays of red hairs, creating a distinct collar as well as contrasting areas ventrally around the thorax, enhance the butterfly's beauty. The remarkable coloration is realized by a diverse number of intricate and complicated nanostructures in the hairs as well as the wing scales. The red collar hairs contain a broad-band absorbing pigment as well as UV-reflecting multilayers resembling the photonic structures of Morpho butterflies; the white wing patches consist of scales with prominent thin film reflectors; the blue patches have scales with ridge multilayers and these scales also have centrally concentrated melanin. The green wing areas consist of strongly curved scales, which possess a uniquely arranged photonic structure consisting of multilayers and melanin baffles that produces highly directional reflections. Conclusion: Rajah Brooke's birdwing employs a variety of structural and pigmentary coloration mechanisms to achieve its stunning optical appearance. The intriguing usage of order and disorder in related photonic structures in the butterfly wing scales may inspire novel optical materials as well as investigations into the development of these nanostructures in vivo

Butterfly gyroid nanostructures as a time-frozen glimpse of intracellular membrane development

The formation of the biophotonic gyroid material in butterflywing scales is an exceptional feat of evolutionary engineering of functional nanostructures. It is hypothesized that this nanostructure forms by chitin polymerization inside a convolutedmembrane of corresponding shape in the endoplasmic reticulum. However, this dynamic formation process, including whether membrane folding and chitin expression are simultaneous or sequential processes, cannot yet be elucidated by in vivo imaging. We report an unusual hierarchical ultrastructure in the butterfly Thecla opisena that, as a solid material, allows high-resolution three-dimensional microscopy. Rather than the conventional polycrystalline spacefilling arrangement, a gyroid occurs in isolated facetted crystallites with a pronounced size gradient.When interpreted as a sequence of time-frozen snapshots of the morphogenesis, this arrangement provides insight into the formation mechanisms of the nanoporous gyroid material as well as of the intracellular organelle membrane that acts as the template

Research Data Supporting "Gyroid Optical Metamaterials: Calculating the Effective Permittivity of Multidomain Samples"

Data Supporting Publication "Gyroid Optical Metamaterials: Calculating the Effective Permittivity of Multidomain Samples"Swiss National Science Foundation, National Center of Competence in Research Bio-Inspired Materials, [200021_163220 and PZ00P2_168223], EPSRC [Cambridge NanoDTC EP/G037221/1, EP/L027151/1, and EP/G060649/1], ERC [LINASS 320503], European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie [706329], Adolphe Merkle Foundatio

Optical Imaging of Large Gyroid Grains in Block Copolymer Templates by Confined Crystallization.

Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography to optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due to their structural isotropy. Here, the aligned crystallization behavior of a semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized to visualize the grain structure of the cubic microphase-separated morphology. Upon quenching from a solvent swollen state, ISO first self-assembles into an alternating gyroid morphology, in the confinement of which the PEO crystallizes preferentially along the least tortuous pathways of the single gyroid morphology with grain sizes of hundreds of micrometers. Strikingly, the resulting anisotropic alignment of PEO crystallites gives rise to a unique optical birefringence of the alternating gyroid domains, which allows imaging of the self-assembled grain structure by optical microscopy alone. This study provides insight into polymer crystallization within a tortuous three-dimensional network and establishes a useful method for the optical visualization of cubic BCP morphologies that serve as functional nanomaterial templates.This research was supported through the Swiss National Science Foundation through grant numbers 163220 (U.S.) and 168223 (B.D.W.), the National Center of Competence in Research Bio-Inspired Materials (U.S., B.D.W, I.G.), the Adolphe Merkle Foundation (B.D.W., U.S., I.G.), the Engineering and Physical Sciences Research Council through the Cambridge NanoDTC EP/G037221/1, EP/L027151/1, EP/N016920/1, and EP/G060649/1 (R.D., J.A.D., J.J.B.), and ERC LINASS 320503 (J.J.B.). This project has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706329/cOMPoSe (I.G.). Y.G. and U.W. thank the National Science Foundation (DMR-1409105) for financial support. Part of the work was conducted at beamline D1 at the Cornell High Energy Synchrotron Source (CHESS); CHESS is supported by the NSF and NIH/NIGMS via NSF award DMR-1332208. We also thank Diamond Light Source for access to beamline I22 (SM13448) that contributed to the results presented here

Accelerating circular economy solutions to achieve the 2030 agenda for sustainable development goals

Circular economy seems a vital enabler for sustainable use of natural resources which is also important for achieving the 2030 agenda for sustainable development goals. Therefore, a special session addressing issues of "sustainable solutions and remarkable practices in circular economy focusing materials downstream" was held at the 16th International Conference on Waste Management and Technology, where researchers and attendees worldwide were convened to share their experiences and visions. Presentations focusing on many key points such as new strategies, innovative technologies, management methods, and practical cases were discussed during the session. Accordingly, this article compiled all these distinctive presentations and gave insights into the pathway of circular economy towards the sustainable development goals. We summarized that the transition to circular economy can keep the value of resources and products at a high level and minimize waste production; the focus of governmental policies and plans with the involvement of public-private-partnership on 3Rs (reduce, reuse, and recycle) helps to improve the use of natural resources and take a step ahead to approach or achieve the sustainability