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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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Investigation of Fe-doped room temperature dilute magnetic ZnO semiconductors
摘要： Different ceramics sample of Zn1-xFexO (ZFO) series have been sintered by solid state reaction method. Single phase polycrystalline Fe-doped ZnO sample with hexagonal wurtzite structure has been obtained with x < 0.03 mol. Segregation of Fe and/or its oxides have not been found in the XRD patterns. A weak secondary phase of ZnFe2O4 has been detected with x ≥ 0.03 mol. Presence of Ohmic conductivity has been detected in the dielectric property analysis and the reasons for this Maxwell-Wagner-Sillars (MWS) relaxation has been explained by the grain boundary barrier defect (GBBD) process. The obtained shift of diamagnetic behavior of pure ZnO samples to para-magnetic for ZFO samples has been established with the defect and impurity structure. The band gap energy for ZFO samples has been calculated between 2.85 eV to 3.15 eV. The results indicate the potential use of Fe doped ZnO ceramics in high frequency device applications.
关键词： Spintronics,XRD,Hysteresis loops,Dilute magnetic semiconductor,Dielectric constant,Optical property
更新于2025-10-22 19:40:53
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Dynamic Magneto-optical Inversion in Magnetic Fluid using NanoMOKE
摘要： Systematic inversion of optical anisotropy with magnetic field sweep (0-5000Gauss) has been observed at a critical concentration in the monodispersed magnetic fluids using NanoMOKE III. This experimental technique is significantly novel method to investigate the optical anisotropy of magnetic nano-suspensions with the time-varying magnetic field. In this work, we report a detailed experimental investigation on the field dependent magneto-optical behaviour of dilute water dispersed Fe3O4 based magnetic fluid. Magnetic fluid shows tunable magneto-optical properties which primarily depends on parameters such as, particle concentration, composition and carrier medium. We have observed a systematic inversion in optical anisotropy at critical concentration for a Fe3O4 magnetic fluid with strong spatial dependence. The observed tuneable magneto-optical phenomena have been correlated to the net effect of the structuration process, electronic transitions and gravitational force in the presence magnetic field. This phenomenon leads to the development of two particle size distribution, negative optical activity initially and strong spatial dependence respectively. The present results provide a strong correlation with theoretical models presented to expound the dependency of various parameters on magneto-optical inversion behaviour of magnetic fluids.
关键词： ferrofluids,Magnetic fluids,optical anisotropy,magnetic Inversion,NanoMOKE
更新于2025-09-23 15:23:52
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Magnetization and magnetic resonance in sol-gel derived polycrystalline BiFeO3 film
摘要： The structure and magnetic properties of polycrystalline BiFeO3 films grown on glass substrate using Sol-Gel technique have been investigated. X-ray diffraction (XRD) analysis revealed the average grain size of about 21 nm. The root mean square (RMS) surface roughness of about 50 nm has been obtained for the film by using scanning electron microscope (SEM) technique. Ferromagnetic resonance (FMR) studies showed the presence of macroscopic ferromagnetic magnetization and uniaxial out-of-plane magnetic anisotropy. The temperature dependences of the magnetization of BiFeO3 films registered in zero field cooling (ZFC) and field cooling (FC) regimes revealed a spin glass state. The average magnetic crystallite sizes obtained from the magnetizations studies coincide with the values revealed from the structural studies.
关键词： sol-gel technique,magnetic properties,magnetic materials,multiferroics
更新于2025-09-23 15:23:52
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Fano-like resonance in large-area magnetic metamaterials fabricated by nanoimprint technique title
摘要： We experimentally and theoretically investigated the Fano-like resonance in large-area magnetic metasurfaces fabricated by nanoimprint lithography technique based on elaborately designed Ag-SiN-Ag configuration. Asymmetric line shape is revealed in reflection spectrum of the magnetic metamaterials. The physical mechanism is elucidated through dispersion relation and electromagnetic field distribution analysis. Both the measured and calculated dispersion relation tell that there are magnetic resonance modes and surface lattices modes coexisting in the magnetic metamaterials, their coupling leads to the asymmetric profile in the reflection spectrum. The calculated electromagnetic field distribution further consolidate the coupling phenomenon in the magnetic metamaterials. This work might significantly prompt the applications of metamaterials in sensing, lasing, and optical devices designing.
关键词： SPP,magnetic resonance,Fano Resonance,surface lattice resonance,magnetic metamaterials
更新于2025-09-23 15:23:52
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Optical Sensing of Broadband RF Magnetic Field Using a Micrometer-Sized Diamond
摘要： High-resolution ?eld imaging with minimized invasiveness is of growing interest with the development of radio frequency (RF) integrated circuits and planar antenna characterization. In this paper, we propose an optical broadband sensor with static offset magnetic ?eld using a diamond crystal that contains an ensemble of nitrogen-vacancy (NV) centers. The spatial resolution of micrometer scale is demonstrated by using a diamond crystal of this size. This technique is based on the modulation of ?uorescence emitting by NV center under green laser excitation, by an off-axis magnetic ?eld at radio frequencies. We demonstrate experimentally the detection of an RF magnetic ?eld, with minimum measurable amplitude on the order of 0.1 Gauss, which is limited by the noise ?oor of the avalanche photodetector. The sensitivity can be further improved by noise suppression in optics. The bandwidth of the sensor is measured to be 15 MHz.
关键词： near-?eld imaging,magnetic ?eld,magnetic resonance,Instrumentation and measurement,real time,laser
更新于2025-09-23 15:23:52
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The Use of Magnetic Orientation as a Pinning Modality for Investigation of Photon-Magnon Interactions in Magnetic Nanoparticle Systems
摘要： In this work, an experimental setup to study the dependence of a visible-light transmission through a magnetic granular film on the magnetic field direction was presented. The results measured the transmission (T) of the visible light, with the wavelengths (λ) were in the range from 560 to 695 nm, by the magnetic nanogranular films Cox-(Al2O3)100-x system, with Co compositions are x = 10 ÷ 45 at.%, as a function of the magnetic field direction were reported. These investigations were carried out under an external magnetic field of H = 400 Oe, which directs to the normal of the sample surface by an angle varied in the range of θ = 0° ÷ 45°, to magnetize the magnetization direction of all the Co particles following this direction. Consequently, the angle θ between the magnetization direction with the incident-light direction, which sets as the optical axis of the system and always keeps fixedly to the normal of the sample surface, is established. The experimental results showed the different dependencies of T on the angle θ, the magnetic field H, the Co composition x, and the wavelength λ. These dependencies attributed to a behavior that relates to so-called photon-magnon interaction.
关键词： Ferromagnetic Nanoparticle (FMNP),Visible-Light Transmission,Magnetic Nanogranular Film (MNGF),Plasmonic Spin,Photon-Magnon Interaction
更新于2025-09-23 15:23:52
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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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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - A Novel Vacuum Interruption Contact Design for High Current DC Vacuum Circuit Breaker
摘要： The vacuum interruption contact structure affect the insulation and breaking performance of DC vacuum circuit breaker directly. A novel vacuum interruption contact system with axial magnetic field (AMF)-double transversal magnetic field (TMF) is investigated for high current interruption in DC vacuum circuit breaker in this paper. It consists of one AMF cup-shaped contact and two concentric TMF contacts, which the internal contact is a disk-shaped structure and the external contact is a cup-shaped structure. The so-called novel TMF-TMF-AMF contact structure has the merits of having a very high axial magnetic flux density at large current condition, and producing rotation Lorentz force for metal vapor arc caused during interruption process. Its performance is compared with that of traditional TMF contact, traditional AMF contact and TMF-AMF contacts using three-dimensional finite-element method and the comparison results verify the validity of this proposed interruption contact structure design.
关键词： Lorentz force,vacuum interruption,finite element method,Axial magnetic flux density,metal vapor arc
更新于2025-09-23 15:23:52
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Positron emission tomography/computed tomography outperforms MRI in the diagnosis of local recurrence and residue of nasopharyngeal carcinoma: An update evidence from 44 studies
摘要： Studies on nasopharyngeal carcinoma (NPC) in five electronic databases were systematically searched online from the inception to June 5, 2018. Quality of the included studies was assessed using the updated Quality Assessment of Diagnostic Accuracy Studies 2. Data of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the 95% confidence intervals were pooled using a bivariate random‐effect model. Forty‐four studies with 61 groups of data and totally 3369 patients were included in the qualitative and quantitative synthesis analysis. The overall estimated sensitivity and specificity of positron emission tomography/computed tomography/magnetic resonance imaging (PET‐CT/MRI) for local recurrent/residual NPC were 0.90 and 0.85, respectively. The pooled area under the curve of (AUC) of PET‐CT/MRI in the summary receiver operator characteristic curve was 0.94. Subgroup analysis showed MRI vs PET‐CT had lower sensitivity (0.83 vs 0.92) and specificity (0.78 vs 0.89). The AUCs of MRI and PET‐CT were 0.87 and 0.96, respectively. No‐cross of 95% CI was found in MRI vs PET/CT (0.87‐0.90 vs 0.94‐0.98). Meta‐regression showed PET/CT vs MRI was a potential source of heterogeneity. PET/CT and MRI both showed quite high overall ability in diagnosing local recurrent/residual NPC, but the subgroup analysis indicated PET‐CT was superior over MRI in diagnosis of local recurrence and residue of NPC after radiotherapy. The examination methods affected the heterogeneity within studies.
关键词： specificity,positron emission tomography/computed tomography,sensitivity,magnetic resonance imaging,recurrence/residue,nasopharyngeal carcinoma
更新于2025-09-23 15:23:52