Diamagnetic Glasses Research Articles

Pb2+/Co2+ modified growth and phase transitions of CsPbBr3 in heavy metal oxide glass with enhanced magnetic and magneto-optical properties

In this study, we investigated the impact of Pb/Co compositional ratios on the growth and phase transition of CsPbBr3 within PbO-Bi2O3-B2O3 glasses. We employed XRD Rietveld refinement and Raman spectra for a thorough analysis of structural modifications and crystal phases. To assess the morphology, size, and distribution of CsPbBr3 crystals, as well as the homogeneity of embedded glasses, we utilized SEM and TEM, along with SAED patterns. The results confirmed a phase transition from cubic CsPbBr3 to tetrahedral CsPb2Br5 at Pb content exceeding 60%, leading, however, to severe crystallization and the transformation of glassy phases into ceramics. Expanding on the optimal 45% PbO content, we also explored the influence of CoBr2. XRD refinement and Raman analysis revealed Co content-dependent growth and phase transition of CsPbBr3 within the glasses. XPS studies demonstrated the coexistence of Co2+ and Co3+ ions, and their spin states and coordination were verified through XANES and EPR analysis. Notably, the presence of high-spin octahedral Co2+ replacing Pb in the B-site of perovskite resulted in observed ferromagnetism in the Co-doped glasses. Magnetization increased within the 1–3% Co content range. Simultaneously, a high-value Verdet constant of 108 rad/T·m at 633 nm was obtained, presenting an attractive feature for diamagnetic glasses.

The role of 4f14 Lu3+ and 3d0 Sc3+ in faraday rotating glass/ceramic: Structural stability, magnetic and magneto optical properties

Magneto-optical materials exhibiting low/no temperature-dependent Faraday rotation, high magnetization and good thermal/mechanical stability are required in various magneto-optical sensing and photonic applications. For the first time, we employed the rare earth Lu3+ and Sc3+ ions to strengthen the structure and enhance magnetic& magneto-optical properties of heavy metal oxide diamagnetic glasses. Experimental results revealed that the doping of Lu2O3 and Sc2O3 not only significantly increased the UV-VIS transmittance, improved the thermal stability, Vicker's hardness and tensile strength, but also remarkably increased the magnetic susceptibility and Verdet constant. The reasons were analyzed through the XRD, FT-IR, Raman spectra, oxygen chemical bonds, EPR of Lu2O3 and Sc2O3 crystal fields and affinity to oxygen. Promising Faraday rotating glass with Verdet constant of 76.32 rad/Tm at 633 nm, thermal stability KH = 0.817, very low thermal expansion coefficient (14.04 × 10−6 K−1) and high diamagnetic susceptibility of 9.25 × 10−6 emu/g has obtained which has potential merits for photonics and MO devices applications.

EPR, Magnetic and Faraday Rotation of Al3o4 Tailored La0.8sr0.2feo3 Crystallization in Diamagnetic Glass

EPR, Magnetic and Faraday Rotation of Al3o4 Tailored La0.8sr0.2feo3 Crystallization in Diamagnetic Glass

Giant Faraday rotation, magnetic and nonlinearity of diamagnetic glass tailored by plasmonic-magnetic bimetallic Au-Ni NPs

Glass containing plasmonic-magnetic nanoparticles have presented striking potential for plasmonic and nonlinear properties. For the first time, we report the synthesis and the magnetic/magneto-optical characterization of plasmonic-magnetic bimetallic Au-Ni nanoparticles (NPs) in heavy metal oxide diamagnetic glasses through co-sputtering technique. The optimum parameters for deposition, diffusion and formation of AuNi NPs were determined and< 50 nm AuNi NPs were synthesized in glass. Compositional and chemical valence states analysis revealed that the NPs is metallic AuNi, oxidization occurred for temperature high than 380 °C. The incorporation of Au-Ni NPs endowed the diamagnetic glass intense SPR peaks and superior optical nonlinearities comparable to that of host and single Au incorporated glasses. The alloy of transition metal Ni contributed to remarkable ferromagnetic character to glasses with characteristic M-H and M-T relations. Giant Verdet constant were obtained for glass and influential reasons were investigated insight of SPR effect, optical energy band gap and magnetization. Glass having 42 nm-AuNi NPs treated at 380 °C for 6 h exhibited huge Verdet constant of 72.66 rad/T m, large third-nonlinear susceptibility of 8.14 × 10−11 esu and strong ferromagnetic moment. This glass will be promising for advanced optical nonlinear and magneto optical applications.

Ta2O5 nanocrystals strengthened linear, nonlinear, and Faraday properties of heavy metal oxide diamagnetic material

AbstractIn this study, for the first time the diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the thermal stability, optical linear and nonlinear, and Faraday rotation of diamagnetic glasses. Temperature‐dependent crystal morphology, phases, and structures of Ta2O5 were studied and 50 nm spherical δ‐Ta2O5 nanocrystal was obtained and shown decreased band gap of 3.68 eV. Transparent Ta2O5 nanocrystal doped diamagnetic glasses were obtained, and the embedded Ta2O5 nanocrystals have size ranging from 50 to 80 nm. EDX, XRD, FT‐IR, and Raman analysis indicated that Ta2O5 partially dissolved into glass as TaO6 octahedral units, while partially residual as undissolved Ta2O5 nanocrystals. Ta5+ ions strengthened the network connectivity of 1%–5% Ta2O5‐doped glasses, but Ta5+ acted as network modifier in 10% doped sample and changed the frame coordination units of glass. Therefore, 1% and 5% Ta2O5‐doped glasses showed high Tg and large thermal stability (107° and 120°). All Ta2O5‐doped glasses exhibited broad and intense optical emission at 420 nm, excellent nonlinear refractive index (5.22 × 10−14 cm2/W) and giant Verdet constant (56.19 rad/T·m) due to the increase in density, polarizability, and diamagnetic susceptibility by Ta2O5 doping.

Mixed valence effects in Pr:YbF3 nanocrystals and influence to EPR, magnetic and Faraday rotation properties of diamagnetic glasses

The co-existence of light and heavy rare earth ions will arouse interesting optical, magnetic and magneto optical properties to matrix due to energy transfer between various rare earth ions and spin-orbit interactions of electric dipoles and magnetic dipoles. Pr and Yb co-doped orthorhombic Pr:YbF3 nano-crystals have been prepared by hydrothermal method, the structure and properties of Pr:YbF3 were characterized using X-ray diffraction, scanning electron microscopy, electron paramagnetic resonance, Raman & Infrared spectra and superconducting quantum interference device. The introduction of Pr into YbF3 induced changes on morphology, structure and properties due to different ionic radius, electronegativity and bond strength.The fabricated Pr:YbF3 nanocrystal doped glasses show good transparency and morphology. Pr:YbF3 nanocrystals were well dispersed in glass with slightly increased size (25 nm). X-ray photoelectron spectra confirmed the co-existence of Yb2+, Yb3+ and Pr3+ in 1% and 2% doped glasses, and additional Pr4+ in 4% doped one. Optical absorption edge red-shifted and emission intensity increased with the doping amount. Energy transfer between Pr3+ and Yb3+ ions was observed around 1000 nm. Due to the electron transition and energy transfer, the magnetization changed from diamagnetic to ferromagnetic and showed temperature-dependent behaviors. The Faraday rotation was significantly reinforced by Pr:YbF3 and a giant Verdet constant of -0.32 min/G.cm was obtained at 533 nm wavelength for 4% Pr:YbF3 doped glass which is promising for magneto optical devices.

Optical nonlinear, EPR, second harmonic generation and Faraday rotation studies on diamagnetic solid: Influence of thermal poling

The electric field manipulation of magnetic and magneto optical properties is currently of great interest for photonics and spintronics devices. In this study, for the first time, we utilized the thermal poling electric field induced polarization and magnetization to manipulate the magnetic and Faraday rotation performance of heavy metal oxide diamagnetic glass. The influence of poling conditions on second & third nonlinearity, structure and defects, thermal, magnetic and magneto optical properties were studied through varies characterization techniques such as scanning electron microscope, X-ray powder diffraction, Raman, maker fringe, electron paramagnetic resonance, X-ray photoelectron spectroscopy, Z-scan, vibration sample magnetometer and Faraday rotation measurements. 5 µm-thickness layer second harmonic generation intensity increased with the voltages from 1 kV to 3 kV, while at 300°C second harmonic generation the intensity decreased. Third nonlinearity coefficient and nonlinear refractive index were calculated to be much higher than that of un-poled glass through the Z-scan method. X-ray photoelectron spectroscopy, Raman and electron paramagnetic resonance analysis revealed the center-asymmetric network of glass, non-bridging oxygen and defect centers after thermal poling. The modification on glass structure resulted in the enhancement of magnetic moment of glass with electric induced magnetic field changes electric coupling effect as high as 15%. Faraday rotation measurement indicated that polarization dominantly contributed to the enhancement of V, at the same time, the V also was impacted by glass transmittance and crystal scattering. The optimized thermal poling condition was determined to be 3 kVand 260°C for 4 hours, under which thermally poled glass presented the strong second harmonic generation intensity (2.3 pm/V), highest Verdet constant (0.2382 min/G.cm) and improved diamagnetic susceptibility (0.424×10−5 emu/mol). Diamagnetic glass with these properties is attractive for magneto optical sensing and nonlinear applications.

Surface plasmon resonance effect, nonlinearity and faraday rotation properties of magneto optical glass: Influence of diamagnetic Ag@ZrO2 nanoparticles

In this study, for the first time we report the influence of Ag@ZrO2 nanocomposites to diamagnetic glass forming ability, structure, Plasmon, nonlinear, hardness and Faraday rotation properties. Spherical Ag@ZrO2 nanocomposites with average 50 nm size were synthesized and well dispersed without oxidation of silver. XRD, XPS, FT-IR and Raman spectra displayed the pure Ag0 and monoclinic ZrO2 phases with typical ZrO2 (m) vibration modes. Due to the high polarizability and large mass, high valence Zr4+ existed in glass as ZrO4 which strengthened the glass network, so good quality and transparent glasses were obtained for 0–3% Ag@ZrO2 doping amount. 3% Ag/ZrO2 containing glass presented strong SPR effect, the biggest hardness of 497HV, giant nonlinear refractive index of 3.44×10−17 m2/W and the highest Verdet constant of 0.2002 min/G.cm which make the glass most suitable for magneto optical, nonlinear and photonic applications.

Thermal, nonlinear, magnetic and faraday rotation properties of sol-gel diamagnetic glass /NaYF4: Fe, Ho3+: Role of magnetic ions

Ho3+ owns the biggest magnetic moment, stark splitting of energy and low-symmetry D2 crystal field which make Ho3+ high polarizable and has been studied as dopant in several magnetic crystals. For the first time, Ho3+ doped sol-gel synthesized diamagnetic glass for nonlinear, magnetic and magneto optical study was reported. This paper reports the synthesis, structure, morphology and magnetization of hexagonal NaYF4:Fe, Ho nanorods and importantly, the influence of NaYF4:Fe, Ho to the thermal, nonlinear, magnetic and Faraday rotation of diamagnetic glasses through varies techniques such as X-ray diffraction, scanning electron microscopy, Raman spectra, Ultraviolet–visible spectra, different scanning calorimetry, thermal mechanical analysis, Z-scan, superconducting quantum interference device magnetometry and Verdet constant measurement. Experimental results discovered that the doping of Ho3+ and Fe3+ ions disturbed the self-assembly of NaYF4 while suppressed the length of nanorod. Due to its nanoscale, magnetization of NaYF4:Fe, Ho changed from diamagnetic to superparamagnetic. The doping of NaYF4:Fe, Ho increased the thermal stability and third nonlinearity. Glass with different amount of doping presented diamagnetism and paramagnetism due to the strongest magnetic moment, increased polarizability, electron transition of Ho3+ and d-d exchange of Fe3+ ions in glass matrix. Glass doped 2% of NaYF4:Fe, Ho glass showed the best magnetic, magneto optical performance and improved thermal stability and nonlinearity which can be ideal candidate for photonics, nonlinear and magneto optical applications.

Sb2O3 functionalized Plasmon, photoluminescence and Faraday rotation in glass

This paper reports the influence of antimony ions and Sb2O3 reduced Ag0 on the magnetic and Faraday rotation of diamagnetic glasses for the first time. High Verdet constant diamagnetic glasses with compositions of xSb2O3–(15–x)B2O3–35PbO–45Bi2O3–2Ag2O–3ZnO were fabricated and characterized. Ag nanoparticles were realized in glass using Sb2O3 as reducing agent through single-step melting quenching technique. The structure, spectral along with optical, magnetic and Faraday rotation properties were investigated through XRD, FT-IR, Raman, XPS, UV-VIS, luminescence and VSM measurements. Due to the big optical basicity of glass matrix and the reducing property of Sb2O3, Ag+ ions were reduced to Ag0 accompanied with the conversion from Sb3+ to Sb5+. Raman spectra revealed the presence of SbO3, BiO3, PbO4, and BO3, BO4 units in glasses, with the increase of Sb2O3, Ag-O and B-O vibration decreased and 10-15% Sb2O3 doped samples crystallized into ceramics. XPS analysis displays the co-existence and evolutions of antimony and silver species as a function of Sb2O3 content. SPR absorption peaks of Ag nanoparticles in glasses red-shifted from 525nm to 600nm, indicating the aggregation of Ag nanoparticles into bigger sized Ag3 clusters which present emission peaks around 560nm. The electron transitions between Sb3+ and Sb5+ show emission around 560nm while Sb5+ ions show emission at 800nm. All glasses exhibited diamagnetic properties due to the diamagnetic character of glass matrix and doping ions. Both the high polarizability of diamagnetic Sb3+&Sb5+ and Ag0 SPR effects contributed to an enhancement of Faraday rotation of glasses, the 3%Sb2O3 doped glass showed the highest Verdet constant of 0.2047min/G.cm at 594nm which therefore might be an attractive candidate for magneto optical device applications.

Cu0&Cu2O nanoparticles functionalized diamagnetic glasses: linear/nonlinear optical, magnetic and Faraday rotation

This paper reports Cu0&Cu2O nanoparticles synthesis and functionalized optical linear/nonlinear, magnetic and Faraday rotation properties of diamagnetic glasses. 40nm pure cubic Cu2O nanoparticles presented fingerprint Fourier transform infrared vibration at 632 cm−1 and characteristic Raman vibration of Cu(I)-O at 219 cm−1. Transparent glasses were obtained for Cu2O doping amount < 0.5 mol% under reducing environment. Cu2O modified glass structure and changed coordination of BiO3 and BO3. Cu0 and Cu+ ions co-existed, Bi4f and O1s changed with Cu2O amount. Cutoff wavelength red-shifted and a Surface Plasmon Resonance peak of Cu nanoparticles appeared at 680 nm whose intensity increased with doping amount. Under 320 nm excitation, glass showed broad and strong luminescence at 560 nm due to 3d94s1→3d10 transitions of Cu+ and Cu0. The synergetic effect of Surface Plasmon Resonance of Cu0 and electron transition of diamagnetic Cu+ greatly enhanced magnetization, nonlinearity, Verdet constant of glass (0.2097 min/G.cm) and figure of merit.

Bi1.9Mn0.1Te3 nanocrystal functionalized diamagnetic glasses: optical, luminescence, magnetic and Faraday rotation

Mn doped Bi2Te3 nanocrystal, both as topological insulator and diluted magnetic semiconductor, has gained significant interest due to its interesting magnetic performance roused by the sp-d exchange interaction and unique time-reversal symmetry protected surface states. In this paper, for the first time, Bi1.9Mn0.1Te3 nanocrystal doped diamagnetic TeO2–PbO–B2O3 glass was studied. Pure 50nm hexagonal Bi1.9Mn0.1Te3 nanocrystals were synthesized with a specific surface area of 64.28 m2/g using the optimized PEG as surfactant. Due to the complex spin-orbit interactions between sp band of Bi2Te3 and d band of Mn, the prepared Bi1.9Mn0.1Te3 displayed characteristic luminescence, A11g, E2g, A21g Raman modes, good photocatalytic (70.2%) and ferromagnetic/paramagnetic co-existence behavior.Bi1.9Mn0.1Te3 doped diamagnetic glasses were prepared by melting-quenching technique and the influence of different doping amount to glass structure and properties was evaluated through X-ray diffraction, Fourier transforms infrared, Raman, Ultraviolet-visible, photoluminescence spectra and Verdet constant measurement. The glasses structure and properties were doping amount dependent. X-ray diffraction, Fourier transforms infrared and Raman spectra revealed the evolution of structure units of TeO4, TeO3, BO3 etc under the modification of Bi1.9Mn0.1Te3. SEM revealed the homogeneity and growth of nanocrystals in matrix. X-ray photoelectron spectroscopy displayed the chemical states changes of Mn2p, Bi4f, Te3d and O1s under different doping amounts. Both the optical absorption band at 540nm and cutoff wavelength increased with the dopant amount. The luminescence in visible range revealed the tetrahedral coordination state of paramagnetic Mn ions which also influenced the magnetization and Faraday rotation accordingly. Experimental results showed that glass with 2%Bi1.9Mn0.1Te3 exhibited good optical, luminescence, magnetic, significant high Verdet constant (0.2522min/G.cm) and good thermal stability as well. Such good quality diamagnetic glass is attractive for magneto-optical devices applications in isolator and current transducer etc.

Optical linear &amp; nonlinearity and Faraday rotation study on V2O5 nanorod doped glass and glass-ceramic: Impact of optical basicity

Abstract Different valence states and coordination units of vanadium in low optical basicity glasses have been extensively studied for conduction, photoluminescence and catalysis applications. For the first time we studied the influence of vanadium ions in high optical basicity diamagnetic hosts to nonlinear and Faraday rotation properties by Scanning electron microscopy, X-ray diffraction, Raman, Fourier transform infrared and Ultraviolet–visible spectra, Z-scan techniques etc. 15 nm-pure phase V2O5 nanorod was synthesized and then doped in heavy metal oxide diamagnetic glass by melt-quenching method. For the same doping content, higher optical basicity was favorable for glass forming while low optical basicity could accelerate cubic Bi2O3 crystals formation. Vanadium coordination units dominantly existed as VO5 in high optical basicity, however, VO4 units increased for higher V2O5 content even at the same optical basicity environment. All samples showed good nonlinear behaviors and decreased energy bandgap. The high polarizability of diamagnetic vanadium ions in high optical basicity matrix increased the Faraday rotation (0.2134 min/G.cm at 633 nm) and Figure of merit (0.58) which are attractive for nonlinear and magneto optical devices applications.

Structural and magneto-optical properties of PbO–Bi2O3–B2O3–Al(PO3)3 glasses

Herein, diamagnetic PbO–Bi2O3–B2O3–Al(PO3)3 glasses are prepared by melt-casting and the influence of phosphorus tetrahedral on the structure and optical properties of the glass has been systematically investigated. Compared to diamagnetic PbO–Bi2O3–B2O3 (PBB) glasses, the original boron chain network has been replaced by the boron-phosphate structure. The metaphosphate forms [PO4] units and expands the glass network, which leads to the decline of density and the increase of refractive index (up to ~2.423 @633 nm). The improvement of the magneto-optical properties performs in that the Verdet constant achieves 0.203 min/G cm at 633 nm and higher magneto-optical figure of merit displays a better optical performance than the diamagnetic glass without metaphosphate.

Mixed samarium valences effect in Faraday rotation glasses: Structure, optical, magnetic and magneto-optical properties

Sm2+ ions are attractive in high density memory applications due to its spectral hole burning property. In this study, for the first time, the influence of mixed valence states of Sm ions to magnetic and magneto optical property of diamagnetic glasses were studied. The chemical valence states of Sm and their modification on glass structure, optical absorption, luminescence, magnetic and Faraday rotation performances were characterized using X-ray Photoelectron Spectroscopy (XPS), X-Ray diffraction, Ultraviolet-visible (UV–Vis), Fourier Transform Infrared (FT-IR), Raman spectra and vibrating-sample magnetization (VSM) measurements, respectively. Characteristic emission peaks due to 5D0→7F0 and 5D0→7F1 transitions of Sm2+ and 5G5/2→6H7/2, 5G5/2→6H9/2 transitions of Sm3+ ions were detected in luminescence spectra, indicating the reduction of Sm3+ to Sm2+. XPS analysis on Sm3d core-level spectra demonstrated the co-existence of Sm2+ and Sm3+ and their evolution was Sm2O3 content-dependent. Optical absorption of 6H5/2→4G5/2, 6F11/2,6F9/2,6F7/2,6F5/2 transitions of Sm3+ ions were observed in UV–VIS spectra, however, the absorption peaks of Sm2+ were covered by the stronger absorption of Pb2+ and Bi3+ ions in the UV region. The refractive index, optical cutoff wavelength and band gap of glasses were changed by the incorporation of highly polarizable Sm ions. Due to the different magnetic ordering of Sm2+ and Sm3+ions, glass doped with 1%Sm2O3 presented diamagnetic nature while glasses doped with higher Sm2O3 exhibited paramagnetic behavior, and the Faraday rotation property also was greatly influenced by magnetization susceptibility. 1%Sm2O3 doped glasses presented the strongest magnetization and biggest Verdet constant of 0.1886 min/G.cm at 633 nm. Several influence factors to Verdet constant such as non-bridging oxygen structure, wavelength, refractive index, magnetic susceptibility and temperature were discussed.

Simple one-step ion exchange enhanced Faraday rotation in heavy metal oxide diamagnetic glasses

Ion exchanges (IE) on silicate, tellurite, borate and phosphate glass have been extensively studied for different objectives such as changing glass refractive index, strengthening glass structure or realizing nanometal-glass systems, however, ion exchange on lead-bismuth-borate diamagnetic glass for Faraday rotation improvement is interesting and attractive for magneto optical glass and magneto optical waveguide devices. In this study, for the first time, we studied the one-step Ag+-Na+ ion exchange on diamagnetic Bi2O3-PbO-B2O3-Na2O (PBBN) glass for the aim of improving diamagnetic properties and providing an efficient route for magneto-optical waveguide. The Ag+-Na+ ions has been sucessfully exchanged at 270 °C for 20 min condition. And without any further heat or H2 treatment after IE, the Ag+ ions and Ag0 nanoparticles co-existed in glass. Heat treatment in H2 after IE not only greatly increased the Ag0 NPs size, but also produced the Bi0 crystals which were not helpful for glass properties. Ag nanoparticles showed characteristic surface plasmon resonance peak at 500–550 nm range. Raman spectra displayed the evolutions of Ag+ and Ag0 in functions of different ion exchange conditions. The UV–Visible and Faraday rotation measurements suggested that high polarizability and diamagnetic susceptibility properties of diamagnetic Ag+ ions and Ag0 nanoparticle induced surface plasmonic effects improved the optical refractive index and magneto optical Verdet constant. A simple linear optical waveguide also were obtained on PBBN glass surface using the optimized IE parameters. The proposed one-step ion exchange technique on diamagnetic glass will be an efficient method for glass properties enhancement and magneto optical waveguide fabrication.

Nb2O5 improved photoluminescence, magnetic and Faraday rotation properties of magneto-optical glasses

The high polarizability, low photon energy, high non-linear character and dual functions in glass network make diamagnetic Nb2O5 attractive to magneto optical glass based photonics and sensing devices. In this paper, we report for the first time the influence of Nb2O5 on glass formation, structure, photoluminescence, magnetic and Faraday rotation properties of heavy metal oxide diamagnetic glass. Results suggested that Nb2O5 doping amount greatly influenced its coordination numbers and roles in glass network. Ni2O5 amount ≤ 5 mol% in glass presented in NiO4 which played glass former role and strengthened the PbO4, BiO6, BiO3 and BO3 units composed glass network connectivity, transparent and homogeneous glasses were obtained. DSC measurement showed that the 1%, 2% and 5%Nb2O5 doping increased the Tg and thermal stability of glass. Nb2O5 doping amount higher than 5% presented as NiO6 units which played glass modifier role in glass which distorted glass structure and produced BiNbO4 and Nb2O5 crystalline. A red-shift of absorption edge from 500 nm to 529 nm was observed for Nb2O5 doped glasses. Due to the high optical basicity of host, niobium existed in glass only as Ni5+, and the electron transfers between O2– and Nb5+ displayed two broad emission bands centered at 376 cm and 493 nm (excited at 267 nm) in photoluminescence spectra. 5Nb2O5–5B2O3–45PbO–45Bi2O3 glass exhibited significant thermal stability (100 °C), good photoluminescence, high magnetic susceptibility (57.32 × 10−6 emu/g), and Verdet constant (0.1713 min/G.cm at 633 nm). The novelty of this work is to combine the high polarizability, dual roles properties of Nb2O5 and the high optical basicity of diamagnetic host glass to achieve a diamagnetic valence of Nb and enhance Faraday rotation performance.

Structure, thermal, magnetic and magneto-optical properties of core/shell Fe3O4@MoS2 doped diamagnetic glasses

Glass containing nanoparticles is attractive for plasmonics and photonics applications due to the significant optical and band gap merits. In this paper, 30/70 nm Fe3O4@MoS2 core/shell nanocomposites were synthesized with a specific surface area of 70.1050 m2/g. XRD spectra revealed the good crystallization peaks of Fe3O4 and MoS2 at 14.4°, 30.1°, 32°, 35.9°, 43.1°, 50.8°, 57.2, and 62.58°, respectively, and the increases of lattice parameter of Fe3O4 and MoS2 confirmed that there was the reaction between them. The vibrations of FeO bonds (616 cm−1), MoS bonds (~600 cm−1) along with A1g of Fe3O4 and characteristic E12g and A1g of MoS2 were displayed in their FT-IR and Raman spectra, respectively, indicating the good core/shell nanostructure of Fe3O4@MoS2.The influence of different Fe3O4@MoS2 doping amounts to glass-forming ability, structure and properties was evaluated through varies characterizations. Fe3O4@MoS2 doping amount higher than 10% could not form homogenous glassy matrix, but formed the ceramic composed of α-TeO2 and 2H-MoS2 crystallines. FT-IR, Raman and XPS spectra showed the vibration of MoO42−, FeO, PbO4, TeO4, TeO3, BO3 groups in glasses, revealing the big modification on structure and the existence of highest Mo6+ states due to high optical basicity of glass. Glass doped 2%Fe3O4@MoS2 presented good network connectivity with good thermal stability (Tx–Tg = 130°) and largest magneto-optical activity (V = 0.1826 min/G.cm) because of the high field strength and high spin polarizability of Fe3O4, diamagnetism nature of Mo6+ in glass and the narrow band gap of Fe3O4 and MoS2.

Magneto-optical properties and temperature dependence of diamagnetic lead borate glasses for fiber-optical current transducer

In this paper, diamagnetic lead borate magneto-optical glasses with an improved Verdet constant, high glass-forming ability and good thermal stability were synthesized to meet the design requirements of fiber-optical current transducers (FOCTs). The structure and performance indexes of the glasses were characterized by Raman spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The Verdet constant of the glass samples can reach 0.1757 min/(G cm) at 633 nm, indicating excellent magnetic rotation properties. In practical applications, FOCTs are often used in complex industrial environments that require high temperature stability. To test the temperature dependence of the diamagnetic lead borate glasses, we constructed a dual-light-path variable-temperature magneto-optical modulation system. The experimental data show that the Verdet constant decreases slowly with increasing ambient temperature; thus, we theoretically analyzed the magneto-optical properties of the diamagnetic glass and the cause of its temperature dependence according to the discrepancy between the experimental results and the Becquerel formulas. We also obtained an empirical formula by fitting the Verdet–temperature curve, thereby providing an evaluation basis and a screening method for further development of FOCT materials.

Fe3O4/Co3O4 core-shell nanocomposites modified structure and properties of heavy metal oxide diamagnetic glasses

Transition metal oxides nanomaterials are attractive for electrical, optical and magnetic applications due to their small polaron hopping, narrow band gap and strong spin-orbit interaction. Herein, 80 nm Fe3O4/Co3O4 core-shell nanocomposites were synthesized and doped to heavy metal oxides glasses to evaluate the influence to glass structure, spectra and properties using varies characterization techniques. SEM, BET and XRD analysis confirm the successful synthesis of core-shell nanocomposites, and XPS, FT-IR and Raman spectra reveal the modification of CoO6 and CoO4 groups on glass frame BiO3, BiO6, PbO4 and BO3 units. UV–VIS spectra show a red-shift on cutoff wavelength with two absorption bands at 550 nm and 750 nm due to 4T1g(F) → 2T1g (H) octahedral transition of Co2+ and 5T2g → 5Eg octahedral transition of Co3+ ions, respecitvely, which in turn contributed to electric conductivity. The evolution of Co2+ and Co3+ and their modification on glass induced changes on thermal, mechanical, magnetic and magneto optical properties.