A range of high quality Ga 1−x Mn x N layers have been grown by molecular beam epitaxy with manganese concentration 0.2  x  10%, having the x value tuned by changing the growth temperature (T g ) between 700 and 590 °C, respectively. We present a systematic structural and microstructure characterization by atomic force microscopy, secondary ion mass spectrometry, transmission electron microscopy, powder-like and high resolution X-ray diffraction, which do not reveal any crystallographic phase separation, clusters or nanocrystals, even at the lowest T g . Our synchrotron based X-ray absorption near-edge spectroscopy supported by density functional theory modelling and superconducting quantum interference device magnetometry results point to the predominantly +3 configuration of Mn in GaN and thus the ferromagnetic phase has been observed in layers with x > 5% at 3 < T < 10 K. The main detrimental effect of T g reduced to 590 o C is formation of flat hillocks, which increase the surface root-mean-square roughness, but only to mere 3.3 nm. Fine substrates' surface temperature mapping has shown that the magnitudes of both x and Curie temperature (T C ) correlate with local T g . It has been found that a typical 10 o C variation of T g across 1 inch substrate can lead to 40% dispersion of T C . The established here strong sensitivity of T C on T g turns magnetic measurements into a very efficient tool providing additional information on local T g , an indispensable piece of information for growth mastering of ternary compounds in which metal species differ in almost every aspect of their growth related parameters determining the kinetics of the growth. We also show that the precise determination of T C by two different methods, each sensitive to different moments of T C distribution, may serve as a tool for quantification of spin homogeneity within the material.

The article presents the technology of laser cladding of metallic powders and a machine for laser microsurfacing developed for this purpose. This specifically designed and manufactured station is based on a three-axis CNC machine, equipped with appropriate laser safety systems and a dust extraction system. A disc laser is used as a source of laser energy, connected with the processing optics by a fibre optic cable. A brush powder feeder with a nozzle for shaping the flow of powder transfers the powder coaxially with the laser beam. The system is integrated with a PC-motion card which acts as a CNC controller. The article also presents the results of laser surfacing experiments, classified in terms of the following criteria: surfacing height, width and depth of penetration, wetting angle and microstructural parameters. The laser power density, powder feeding rate and density, as well as the relative movement of the welding head against the component, have been selected as independent parameters.

system laserowego mikronapawania proszków metali system for laser microcladding of metal powders Dr inż. Tomasz Baraniecki, prof. dr hab. inż. Edward Chlebus, mgr inż. Marian Dziatkiewicz, mgr inż. Jakub Kędzia, dr inż. Jacek Reiner, mgr inż. Marcin Wiercioch -Politechnika Wrocławska. StreszczenieW artykule przedstawiono technologię laserowego napawania proszków metali oraz opracowaną dla niej obrabiarkę do laserowego mikronapawania proszków. Zaprojektowane i wykonane stanowisko bazuje na trzyosiowej obrabiarce CNC, którą wyposażono w odpowiednie układy bezpieczeństwa laserowego i pyłowe-go. Jako źródło energii laserowej wykorzystano laser dyskowy sprzężony światłowodem z optyką obróbkową. Szczotkowy podajnik proszków wraz z dyszą kształtują-cą strumień proszku zapewnia jego podawanie współ-osiowo z wiązką lasera. Układ został zintegrowany z kartą PC-motion, która pełni rolę sterownika CNC.Przedstawiono również uzyskane wyniki napawania laserowego, charakteryzując je w kryteriach: szerokości i wysokości ściegu, głębokości wtopienia, kąta zwilżania oraz parametrów mikrostrukturalnych. Jako parametry niezależne przyjęto gęstość mocy wiązki lasera, pręd-kość i gęstość podawania proszku oraz względny posuw głowica-przedmiot. AbstractThe paper presents the technology of laser cladding of metallic powders with a machine for laser microcladding, developed in-house. The designed and constructed set-up is based on a three-axis CNC machine, equipped with appropriate laser safety and a dust extraction system. A disk laser is used as a source of energy, connected with processing optics by a fibre cable. A rotating brush powder feeder transfers the powder to a cladding nozzle, which provides the powder coaxially with the laser beam. The integration of system components is based on a PC-motion card that acts as a CNC controller.Additionally, first results of experiments carried-out on the machine are presented, with characterisation in terms of the cladding height, width and depth, the wetting angle and microstructural features. As independent processing variables the laser power density, the powder feeding rate and the processing speed were used.

No abstract

In this paper, a brief introduction to the Hybrid sensor platforms of integrated photonic systems based on ceramic and polymer materials (HYPHa) is presented. The project's goal is to establish a collaborative effort of institutes specialized in integrated optics. The newly formed group of professionals will be founded on research groups' experience, collaboration, and devotion. We intend to develop a method for combining competencies and a universal material platform for integrated photonics, based on newly validated hybrid materials as part of the project. Silica compounds with additions including TiO2, SnO2, used as structural matrices, polymer coatings with dopants (active or protective layers), organic dyes, and active two-dimensional materials such as transition metal dichalcogenides, graphene hybrids, and boron nitride will be the foundation for these materials. Full Text: PDF ReferencesK. Rola, A. Zajac, M. Czajkowski, A. Szpecht, M. Zdonczyk, M. Smiglak, J. Cybinska, K. Komorowska, "Ionic liquids for active photonics components fabrication", Opt. Mater. 89, 106-111 (2019). CrossRef D. Kowal, K. Rola, J. Cybinska, M. Skorenski, A. Zajac, A. Szpecht, M. Smiglak, S. Drobczynski, K. Ciesiolkiewicz, K. Komorowska, "Fluorescent ionic liquid micro reservoirs fabricated by dual-step E-beam patterning", Mater. Res. Bull. 142, 111434 (2021). CrossRef T. Martynkien, J. Olszewski, M. Szpulak, G. Golojuch, W. Urbanczyk, T. Nasilowski, F. Berghmans, and H. Thienpont, "Experimental investigations of bending loss oscillations in large mode area photonic crystal fibers", Opt. Express 15, 13547-13556 (2007). CrossRef E. Środa, J. Olszewski, and W. Urbańczyk, "Reducing bend-induced loss and crosstalk in a two-mode ridge waveguide by steplike thickness structuring", Appl. Opt. 61, 1164-1170 (2022). CrossRef P. Karasinski, C. Tyszkiewicz, A. Domanowska, A. Michalewicz, J. Mazur, "Low loss, long time stable sol–gel derived silica–titania waveguide films", Mater. Lett. 143, 5-7 (2015). CrossRef P. Karasinski, C. Tyszkiewicz, A. Maciaga, I.V. Kityk, E. Gondek, "Two-component waveguide SiO2:TiO2 films fabricated by sol–gel technology for optoelectronic applications", J. of Mater. Sci.: Mater. Electron. 26, 2733-2736 (2015). CrossRef M.A. Butt, A. Kazmierczak, C. Tyszkiewicz, P. Karasinski, R. Piramidowicz, "Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications", Sensors 21, 7452 (2021). CrossRef A. Kazmierczak, M. Slowikowski, K. Pavlov, M. Filipiak, M. Vervaeke, C. Tyszkiewicz, H. Ottevaere, R. Piramidowicz, P. Karasinski, "Efficient, low-cost optical coupling mechanism for TiO2-SiO2 sol-gel derived slab waveguide surface grating coupler sensors", Opt. Appl. 50, 539 (2020). CrossRef M.A. Butt, S.N. Khonina, N.L. Kazanskiy, "A highly sensitive design of subwavelength grating double-slot waveguide microring resonator", Laser Phys. Lett. 17, 076201 (2020). CrossRef N.L. Kazanskiy, M.A. Butt, S.N. Khonina, "Silicon photonic devices realized on refractive index engineered subwavelength grating waveguides-A review", Opt. Laser Technol. 138, 106863 (2021). CrossRef M.A. Butt, S.N. Khonina, N.L. Kazanskiy, "Recent advances in photonic crystal optical devices: A review", Opt. Laser Technol. 142, 107265 (2021). CrossRef L. Xu, Y. Wang, E. El-Fiky, D. Mao, A. Kumar, Z. Xing, Md. G. Saber, M. Jacques, D.V. Plant, "Compact Broadband Polarization Beam Splitter Based on Multimode Interference Coupler With Internal Photonic Crystal for the SOI Platform", J. Light. Technol. 37, 1231 (2019). CrossRef R. Marchetti, C. Lacava, A. Khokhar, X. Chen, I. Cristiani, D.J. Richardson, G. T. Reed, P. Petropoulos, P. Minzioni, "High-efficiency grating-couplers: demonstration of a new design strategy", Sci. Rep. 7, 16670 (2017). CrossRef