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Tunable magnetic and fluorescent properties of Tb3Ga5O12 nanoparticles doped with Er3+, Yb3+, and Sc3+
摘要： In this study, we present the synthesis of Tb3Ga5O12 nanoparticles doped with Er3+, Yb3+, and Sc3+ ions, prepared using a co-precipitation method. These materials have well-defined magnetic-fluorescence properties. The effects of Yb3+ ion concentration on the structural characteristics, morphology, luminescence, and magnetic properties of the nanoparticles were investigated in detail using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, photoluminescence spectroscopy, and vibrating sample magnetometer measurements. Under 980-nm laser diode excitation, the nanoparticles displayed bright up-conversion luminescence, showing evidence of resonant energy transfer from the Yb3+ to Er3+ ions. Intense green and red emissions located at approximately 526, 548, and 656 nm were attributed to the radiant transitions of 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 of Er3+, respectively. These observations indicate that Tb3Ga5O12:Er3+, Yb3+, Sc3+ magnetic–fluorescent bifunctional nanoparticles are promising materials for use in bioimaging and magnetic bio-separation applications.
关键词： magnetic properties,lanthanide-doped materials,nanoparticles,rare-earth metal,terbium gallium garnet (Tb3Ga5O12),up-conversion luminescence
更新于2025-11-14 15:26:12
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Preparation of Bi<sub>2</sub>Gd<sub>1</sub>Fe<sub>5</sub>O<sub>12</sub> magnetic garnet films showing Faraday rotation of 36.3 deg./μm on glass substrates by metal organic decomposition method
摘要： We fabricated the Bi2Gd1Fe5O12 thin films on glass substrates with the Gd3Fe5O12 buffer layer by the metal organic decomposition (MOD) method. We found an optimum thickness of the Gd3Fe5O12 buffer layer and annealing temperature for crystallization giving the maximum Faraday rotation. The optimum sample showed Faraday rotation of as high as 36.3 deg./μm at the wavelength λ = 500 nm, which is 23 times larger than the sample without the Gd3Fe5O12 buffer layer, and as high as 90.1% of the single crystalline Bi2Gd1Fe5O12 thin films on an (111) SGGG single crystal substrate. These results are promising for applications in optical waveguide isolators and magneto-optic spatial light modulators.
关键词： metal organic decomposition,crystallization process,Faraday rotation,photonic integrated circuits,magnetic garnet
更新于2025-09-23 15:23:52
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Spectroscopic peculiarities of excitation and emission processes as well as relaxation dynamic of excited states in doubly and triply doped Gd3Ga3Al2O12:Ln3+ (Ln3+=Eu3+, Tb3+, Ce3+) crystals
摘要： Spectroscopic properties of Gd3Ga3Al2O12 (GGAG) single crystals co-doped with various configurations of (Eu + Tb); (Eu + Ce); (Tb + Ce) and (Eu+ Tb + Ce) ions have been investigated. The effect of distinct Ln3+ co-doping variations on luminescence of garnet crystals was studied using the different excitation wavelengths. The Ln3+-Ln3+ and host-Ln3+ interplays have been considered in doubly and triply doped GGAG:Ln3+. The crystals containing cerium ions are characterized by mainly broadband emission in the 450–750 nm spectral region that is adequately modified in green and red spectral range in the samples co-doped with terbium and europium, respectively. The Eu3+ luminescence in materials under study is selectively excited employing solely f-f europium transitions. Contrary to that, emission of terbium and cerium occur as result of interaction with Gd3+ and adjacent co-dopants.
关键词： GGAG garnet crystals,Luminescence,Ln-Ln energy transfer
更新于2025-09-23 15:23:52
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Scintillation properties of Ce-doped Yb3Al5O12 single crystals
摘要： Yb3Al5O12 (YbAG) single crystals were prepared by the Floating Zone (FZ) method with and without doping with different concentrations of Ce, and then we evaluated their basic scintillation properties. All the samples showed scintillation with emission peaks in the range from 300 nm to 600 nm. The origin of this emission peak was attributed to the charge transfer luminescence of Yb3+. In addition, the Ce-doped samples showed three strong emission bands, in which the emission origin is also predominantly due to the charge transfer emission but the spectrum was deformed due to a self-absorption by the 4f-5d transitions of Ce3+. Scintillation decay profiles of all the samples were approximated by a sum of two exponential decay functions, and the obtained decay times were 1 and 9-10 ns. Among the present samples, the 0.5% Ce-doped sample showed the lowest scintillation afterglow level. All the samples demonstrated a full energy peak in the pulse height spectrum measured under 241Am 5.5 MeV α-ray irradiation. Among the present samples, the undoped sample showed the highest light yield with a value of 20 ph/5.5MeV-α.
关键词： Ce3+,Charge transfer luminescence,Garnet,Scintillation
更新于2025-09-23 15:23:52
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Preparation of thulium iron garnet ceramics and investigation of spin transport properties in thin films
摘要： Compensated ferrimagnetic thulium iron garnet ceramics were prepared by the sol-gel method, which is significantly better than conventional solid-state reactions. Saturation magnetization yielded a maximum of 16.7 emu/g for specimens sintered at 900 °C. Subsequently, using the TmIG bulk as the target, an epitaxial film was grown by pulsed laser deposition. Furthermore, the spin transport properties of film with an attached 5 nm-thick platinum layer were studied in terms of longitudinal spin Seebeck effect (LSSE) and spin Hall magnetoresistance (SMR). The LSSE coefficient was as high as 0.38 μV/K and the SMR was 0.0072%. These results indicated that the bulk material and thin film presented excellent qualities, which are extremely important for the fundamental investigation of novel spin transport behaviour in compensated ferrimagnetic insulators. These results also provide more alternatives for spintronic materials.
关键词： Magnetic insulators,Thulium iron garnet,Spin transport properties,Compensated ferrimagnet
更新于2025-09-23 15:22:29
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Strong Coupling of Magnons to Microwave Photons in Three-Dimensional Printed Resonators
摘要： We report on ferromagnetic resonant mode hybridization in re-entrant cavities made with a commercial three-dimensional (3D) printer, followed by conventional 3D metalization with copper and tin. The cavity volume was only 7% that of a standard cavity resonating at the same frequency, while maintaining a high quality factor. Simulations were in very good agreement. We obtained an effective coupling of about 40 MHz in two cavities at room temperature. These experimental results demonstrate the utility of tunable filters based on complex 3D printed cavities.
关键词： magnon photon polariton,3D Cavity spintronic,Yttrium Iron Garnet,3D printing,tunable filter
更新于2025-09-23 15:22:29
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Prospective scintillation electron detectors for S(T)EM based on garnet film scintillators
摘要： The performance of a scintillation electron detector for a scanning electron microscope and/or a scanning transmission electron microscope (S(T)EM) based on new epitaxial garnet film scintillators was explored. The LuGAGG:Ce and LuGAGG:Ce,Mg film scintillators with chemical formula (Ce0.01Lu0.27Gd0.74)3–wMgw(Ga2.48Al2.46)O12 were prepared and their cathodoluminescence (CL) and optical properties were studied and compared with the properties of current standard bulk single crystal YAG:Ce and YAP:Ce scintillators. More specifically, CL decay characteristics, CL emission spectra, CL intensities, optical absorption coefficients, and the refractive indices of the mentioned scintillators were measured. Furthermore, electron interaction volumes with absorbed energy distributions, photomultiplier (PMT) photocathode matchings, modulation transfer functions (MTF), and the photon transport efficiencies of scintillation detectors with the mentioned scintillators were calculated. A CL decay time for the LuGAGG:Ce,Mg film scintillator as low as 28 ns with an afterglow of only 0.02% at 1 μs after the e-beam excitation was observed. As determined from calculated MTFs, the scintillation detectors with the new film scintillators lose contrast transfer ability above 0.6 lp/pixel, while the currently commonly used YAG:Ce single crystal scintillators already do so above 0.1 lp/pixel. It was also calculated that the new studied film scintillators have an 8% higher photon transfer efficiency, even for a simple disk shape compared with the standard bulk single crystal YAG:Ce scintillator. The studied LuGAGG:Ce,Mg epitaxial garnet film scintillators were evaluated as prospective fast scintillators for electron detectors, not only in S(T)EM but also in other e-beam devices.
关键词： electron detector,multicomponent garnet film,scintillator,STEM,SEM,LuGAGG:Ce,Mg,cathodoluminescence
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Ann Arbor, MI (2018.7.16-2018.7.18)] 2018 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) - Nonlinear Equivalent-Circuit Model for Thin-Film Magnetic Material Based RF Devices
摘要： A nonlinear equivalent-circuit model is developed for thin-film magnetic material based RF devices such as frequency-selective limiter (FSL) and signal-to-noise enhancer (SNE). The ferromagnetic resonance is modeled by a RLC parallel circuit with parameters derived from Kittel’s equations. The nonlinear effect in magnetic material is represented by a pendulum model that predicts cross-frequency coupling as well as parametric oscillations of spins. The coupling of spin waves in different orders is also modeled by coupled nonlinear pendulum resonators with the exchange coupling between the spins represented by coupling inductors. The measurement results of a FSL in literature are used as a reference, and the model successfully predicts the threshold power level, nonlinear insertion loss, and frequency selectivity of the device.
关键词： Ferromagnetic resonance (FMR),Yttrium iron garnet (YIG),nonlinear model,thin film,frequency selective limiter (FSL)
更新于2025-09-23 15:21:21
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Equine Surgery || Lasers in Veterinary Surgery
摘要： Surgical lasers facilitate minimally invasive surgery, allow surgical access to otherwise inaccessible areas, and induce tissue interactions, which cannot be obtained with conventional surgical instrumentation. Surgical laser procedures can be performed on an outpatient basis and have eliminated procedures that previously required general anesthesia and hospitalization. Surgeons should be knowledgeable about which procedures can be accomplished with surgical lasers and which are better suited to conventional surgery. This chapter will provide information and guidelines on the use of surgical lasers in equine surgery.
关键词： equine surgery,minimally invasive surgery,carbon dioxide laser,Surgical lasers,neodymium:yttrium-aluminum-garnet laser,holmium:yttrium-aluminum-garnet laser,diode laser
更新于2025-09-23 15:21:01
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Anion-Substituted Garnets Ca3Mn2 – x(Ni, Co)xVyGe3 – yO12 (x = 0, 1; y = 0, 1, 2): Preparation and Characterization
摘要： Garnets with the structure similar to that of Ca3Mn2Ge3O12 have been prepared with simultaneous substitutions of Ge4+ by V5+ in tetrahedra and of Mn3+ by Ni2+ or Co2+ in octahedra. X-ray photoelectron spectroscopy (XPS) proved the absence of V4+ in tetrahedra of the lattice of the compounds prepared and determined the valences of elements in octahedral sites. The increasing d-cation size in octahedra is accompanied by an increase in unit cell volume regardless of the composition of tetrahedra (VyGe3 – y)O12. The electrical conductivity of Ca3Mn2 – x(Ni, Co)xVyGe3 – yO12 (x = 0, 1; y = 0, 1, 2) garnet ceramic samples and the calculated bandgap widths make it possible to classify them with medium-gap semiconductors.
关键词： garnet,crystallographic radius,tetrahedron,electrical conductivity,octahedron,bandgap width,d elements
更新于2025-09-23 15:21:01