Dy Doping Research Articles

Correlated Temperature and Field Dependent Magnetization: Enhanced Magnetism Upon Dy Doping in La Cuprate Francisite

Correlated Temperature and Field Dependent Magnetization: Enhanced Magnetism Upon Dy Doping in La Cuprate Francisite

Correlated Temperature and Field Dependent Magnetization: Enhanced Magnetism Upon Dy Doping in La-Based Francisite

Correlated Temperature and Field Dependent Magnetization: Enhanced Magnetism Upon Dy Doping in La-Based Francisite

Synthesis and Evaluation of Znal2o4 and Mn, Dy Doped Znal2o4 Powders by Sol-Gel and Ball Milling Method

Synthesis and Evaluation of Znal2o4 and Mn, Dy Doped Znal2o4 Powders by Sol-Gel and Ball Milling Method

Structural and Magnetic Properties of Dy Doped Sr1-Xdyxfe12o19 Ferrites

Structural and Magnetic Properties of Dy Doped Sr1-Xdyxfe12o19 Ferrites

Improved Temperature-Stable Piezoelectricity and Non-Contact Optical Low-Temperature Sensing Performance in Dy Doped Knn-Based Multifunctional Ceramics

Improved Temperature-Stable Piezoelectricity and Non-Contact Optical Low-Temperature Sensing Performance in Dy Doped Knn-Based Multifunctional Ceramics

The role of Dy doping on cyclic oxidation behavior of Al-Si coating on new cobalt-based γ/γ′ superalloy

The Al-Si-Dy coating is prepared on the γ′-strengthened cobalt-based superalloys by pack cementation method. Cyclic oxidation resistance of the coating at 1050 ℃ is investigated through experimental and computing methods. The cycle oxidation life of the coating is more than 1.5 times that of Al-Si coating. The oxide scale on Al-Si-Dy coating is denser and has stronger adhesion compared to Al-Si coating. Dy doping improves the cyclic oxidation resistance of Al-Si coated sample. The superior cyclic oxidation resistance of the coating is ascribed to enhanced adhesion energy of oxide scale, which is caused by stronger Dy–O bond.

Effect of Reducing and Oxidizing Atmosphere on Photoluminescence of Undoped, Eu Doped and Dy Doped Nanostructured CaAl2O4

Monocalcium aluminate (CaAl2O4) doped with Eu2+ is a phosphor that produces phosphorescence in the blue light (440 nm). It has attracting a great deal of attention because of its wide applications in energy-efficient illumination systems and information displays. CaAl2O4 codoped with Eu2+ and Dy3+ exhibits a very strong and long lasting persistence luminescence that could have many applications in the fields of emergency lighting signs, night-vision signage, in vivo bioimaging, dosimetry and optical data storage.In this work, we present the effect of the thermal treatment in the reducing (nitrogen) and oxidizing (air) atmosphere on the photoluminescence (PL) properties of nanostructured undoped CaAl2O4, CaAl2O4:Eu and CaAl2O4:Dy synthesized by the combustion method. The synthesized powders were characterized by XRD, SEM-EDS, FTIR and Raman techniques. The XRD analysis revealed that the powder mainly consists of krotite (CaAl2O4) together with a small amount of grossite (CaAl4O7) and mayenite (C12Al14O33).The 3D excitation-emission spectra of undoped and untreated CaAl2O4 exhibits a broad band with excitation/emission maximum at 338/412 nm, respectively. The thermal treatment slightly shift the position of the maximum for both the reducing and oxidizing atmosphere. It is interesting to note that the emission peak is red-shifted as the excitation wavelength red-shifts in the untreated sample while the emission peak positions are independent of the excitation wavelength in both reduced and oxidized samples. It is interesting to note that the emission peak shifts to red as the excitation wavelength shifts to red in the untreated sample, while the emission peak positions are independent of the excitation wavelength in reducing or oxidizing samples.The Eu doped sample treated in the oxidizing atmosphere exhibit the typical Eu3+ emission sharp bands while the reduced Eu doped sample reveals only broad Eu2+ emission band that partially overlaps with the band observed in undoped samples. The Dy doped samples exhibit the typical Dy3+ emission sharp bands regardless of their reducing or oxidizing thermal treatment.

Structural and transport properties of Y1-x(Dy)xPdBi (0 ≤ x ≤ 1) topological semi-metallic thin films

We report the effect of 4f electron doping on structural, electrical, and magneto-transport properties of Dy doped half Heusler Y1-x(Dy)xPdBi (x = 0, 0.2, 0.5, and 1) thin films grown by pulsed laser deposition. The electrical transport measurements show a typical semi-metallic behavior in the temperature range of 3 K ≤ T ≤ 300 K and a sharp drop in resistivity at low temperatures (<3 K) for all the samples. Magneto-transport measurements and Shubnikov de-Hass oscillations at high magnetic fields demonstrate that for these topologically non-trivial samples, Dy doping induced variation of spin–orbit coupling strength and lattice density plays an active role in modifying the Fermi surface, carrier concentration, and the effective electron mass of massless carriers. There is a uniform suppression of the onset of superconductivity-like phenomena with increased Dy doping, which is possibly related to the increasing local exchange field arising from the 4f electrons in Dy. Our results indicate that we can tune various band structure parameters of YPdBi by f electron doping, and strained thin films of Y1-x(Dy)xPdBi show surface dominated relativistic carrier transport at low temperatures.

Influence of Dy3+doping concentration on crystal structure and optical absorption of SnO2 nanoparticles

The present work focuses on studying the effect of Dy doping on the structural and optical properties of SnO2 nanoparticles. We prepared the pure and Dy3+ (1, 2, 3 and 4 at %) doped SnO2 nanoparticles sample using the co-precipitation method. Three different techniques XRD, UV– Vis & FTIR spectroscopy, have been used to characterize the prepared sample. X- Ray diffraction was used to determine the crystal structure and crystallite size of the prepared sample. Structural analysis by XRD confirms the substitution of Dy3+ atoms on the sites of the host matrix (SnO2). Tetragonal rutile structure is formed by pure and Dy- doped at different concentrations. UV–VIS spectroscopy was used to study the optical properties of the sample. Optical study shows that the prepared sample is highly transparent and absorption increases with Dy doping concentration due to the increase of defect state. The band gap of the sample was found to decrease with increasing Dy concentration, this is due to defect level formation below the conduction band. FTIR spectroscopy determines the molecular geometry, inter and intermolecular interaction and type of functional group present in the prepared sample.

Investigation of Structural, Dielectric, and Optical Behaviour of Dysprosium-Doped Barium Titanate Ceramics

The influence of Dysprosium (Dy) doping on the structure, dielectric and optical properties of the BaTiO3 system has been investigated in the manuscript. The solid-state reaction method was employed to prepare ceramics with compositions of Ba1−xDy2x/3TiO3 (x = 0.0, 0.01, 0.025, 0.05, 0.075, and 0.1). X-ray diffraction (XRD) structural analysis was carried out, showing complete dissemination of Dysprosium in the BaTiO3 lattice with a tetragonal symmetry. Close investigation of the XRD pattern revealed the existence of a small secondary phase above x ≥ 0.025. Microstructure was analyzed using scanning electron microscopy, showing that grain growth was suppressed by the incorporation of Dysprosium. Raman spectra further confirmed crystal symmetry and existence of a secondary phase for higher doping concentrations. Dielectric behavior was studied with variations of frequency and temperature. The temperature variant dielectric constant and dielectric loss represent a decrease of dielectric constant and loss with a rise in dysprosium content with a slight variation of transition temperature. Temperature coefficient of capacitance values for all compositions were calculated. The diffusivity parameter for all compositions was obtained using modified Curie-Weiss law and an enhancement in diffusivity was observed with increased dysprosium content. The optical behaviour of the doped samples was studied via UV–visible spectroscopy and the optical band gap was found to decrease with doping.

Observation of antiferromagnetic ordering from muon spin resonance study and the Kondo effect in a Dy-doped Bi2Se3 topological insulator

The transport and magnetic properties as well as the microscopic electronic properties of the Dy-doped topological insulator Bi2Se3 (Bi1.9Dy0.1Se3) are examined in detail. It is demonstrated that Dy doping induces antiferromagnetic (AFM) ordering in Bi2Se3. It is also observed that Dy doping opens a surface band gap of ∼52 meV at 6.5 K. The transition from AFM to ferromagnetic occurs at a lower temperature, ∼5 K in a magnetic field of ∼3 T. Furthermore, Dy doping in Bi2Se3 leads to the Kondo effect and weak localization to weak anti-localization crossover. Muon spin resonance measurements indicate that the signal measured with magnetization reflects the magnetic properties of 2% of the sample. The experimental findings are supported by theoretical calculations based on density functional theory.

Role of dysprosium doping concentration on structural deformation of zinc oxide nanoparticles

A small change in crystal structural leads towards a significant improvement in absorption, emission, magnetic nature and electrical properties of ZnO. The present work focuses on studying of Dy+3 doping on structural parameters and absorption analysis of ZnO nanoparticles. Different concentrations of Dy (0–3%) doped ZnO nanoparticles have been synthesized by co-precipitation method without any impurity phase to analyze the role of dysprosium doping concentration on HCP structure of ZnO nanoparticles. We observed variation in structural parameters indicating small deformation due to Dy doping. Absorption spectra specify a slight variation in optical bandgap caused by doping Dy+3. The FTIR peak at 600 cm−1 confirms the ZnO HCP structure. The Dy doping results a wave number shift towards the higher side. The change in wave number is due to atomic mass difference. The study indicates a correlation between variation in absorption spectra and structural deformation.

Enhanced multiferroic properties of relaxor bulk and thin film Na0.5Bi0.5TiO[formula omitted] by ion doping: Theoretical study

We have calculated the spontaneous polarization Ps of ferroelectric Na0.5Bi0.5TiO3 (NBT) thin films. Ps increases with decreasing film thickness due to size and surface effects. It increases with increasing Dy and Nd ion doping and decreases by Er and Ho ion doping due to the different strain caused by the difference in the doping and host ion radii. Transition metal ion doping leads to appearance of ferromagnetism, i.e. of multiferroic properties at room temperature. The temperature dependence of the dielectric constant ϵ′ shows anomalies at both temperatures, Td and Tm. ϵ′ decreases with increasing magnetic field. The critical exponents γ, β and δ are observed for bulk and thin film NBT. The value of γ = 1.55 confirms the relaxor behavior of NBT.

Unraveling Trapping Defects Distribution using Thermoluminescence in Gamma‐Irradiated SrZnO2:Dy Nanophosphors

Thermoluminescence (TL) analysis of gamma‐irradiated SrZnO2:Dy nanophosphors elucidates the presence of various trapping centers in forbidden band. Raman and Fourier‐transformed infrared spectra indicate effect on vibrational structure upon doping. Complex glow curves are obtained at varying gamma radiation doses, exhibiting glow features in low (50–180 °C) and high (220–400 °C) temperature regions. The deconvolution of glow curves indicates the presence of TL peaks at ≈100, 143, 202, 269, and 337 °C. The effect of Dy doping is observed as emergence of new glow feature at ≈143 °C. The substitution of trivalent Dy into SrZnO2 host having divalent cations is proposed to be creating (X = Sr, Zn) electron traps and hole traps, along with hitherto existing intrinsic defects. The concentration quenching of TL signal is perceived at 3 mol% Dy doping, whereas comparing glow curves for all samples at saturation dose indicate quenching of low‐ and high‐temperature glow features at different doping concentrations. The theoretical track interaction model and empirical three trap one recombination center (3T1R) model is used to explain former and latter effects, respectively. A schematic band model is proposed to predict the trap distribution upon Dy inclusion, responsible for observed TL in SrZnO2:Dy nanophosphors.

Dy-doped MoO3 nanobelts synthesized via hydrothermal route: Influence of Dy contents on the structural, morphological and optical properties

This experimental work reports undoped and Dy-doped MoO3 nanobelts with different doping concentrations (1, 2, 3, 4 M%) synthesized via hydrothermal route. The influence of Dy dopant contents on structural, morphological, elemental, functional and optical properties of MoO3 nanobelts was investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FTIR) and UV-Vis-NIR diffuse reflectance spectrophotometer (DRS), respectively. The XRD results supported by FTIR spectra revealed that both types of undoped and Dy-doped MoO3 consist of a combination of orthorhombic and hexagonal phases and all samples are polycrystalline. The randomly oriented nanobelt-like morphology with an average length of 2.023–2.599 µm and average width ranges from 140 nm to 189 nm for undoped MoO3 was identified from FESEM micrographs. Interestingly, no visible change was observed in morphology due to Dy incorporation in pure MoO3 nanobelts. The comparative studies of various structural parameters (i. e. crystallite size, dislocation density, and lattice strain) were evaluated using Debye–Scherrer (D-S) and Williamson–Hall (W–H) formulae. The existence of different functional groups combining both hexagonal and orthorhombic structures of undoped and doped samples was identified which implied the peak intensities and wavenumbers were found to vary slightly. The DRS spectra revealed that optical bandgap increases from 2.95 eV to 3.05 eV up to 3 M% Dy doping and there after decreased to 2.86 eV for 4 M%. This report highlights a noteworthy impact of Dy3+ ions doping on the microstructural, morphological and optical characteristics of MoO3 nanobelts.

Dysprosium doping effects on perovskite oxides for air and fuel electrodes of solid oxide cells

Solid oxide cells (SOCs) which can be operated as a solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) have tremendous attention as a next-generation energy device. To improve the SOCs, recently the atmospheric adaptive materials (AAMs) which can change the crystal structure by themselves to the atmosphere have been studied and reported. As an approach to develop the AAMs, the Dy doping strategy was applied to both air and fuel electrodes for SOCs with various doping amounts from 0 to 50 wt%. Among the samples, the 10% Dy doped Pr0.5Ba0.5MnO3-d shows the best improvements on the catalytic properties and electrochemical performances for both air and fuel electrode. The symmetrical cell with the 10 wt% Dy doped Pr0.5Ba0.5MnO3-d exhibits the maximum power density of 0.175 W cm−2 at 850 °C in SOFC mode and current density of −0.554 A cm−2 at 850 °C at 1.5 V in SOEC mode, respectively. The study demonstrates that the Dy doping strategy is effective on both air and fuel electrodes and is a promising approach to improve the electrochemical performances for both SOFC and SOEC.

Influence of Dy doping on the structural, vibrational, optical, electronic, and magnetic properties of SnO2 nanoparticles

Influence of Dy doping on the structural, vibrational, optical, electronic, and magnetic properties of SnO2 nanoparticles

Hydrothermal Synthesis of Nd–Fe–B Nanoparticles with Enhanced Magnetic Properties by Nd Content Tunning and Dy Doping

This paper reports a novel, facile and low-energy consumption chemical method to synthesise Nd–Fe–B and Dy-substituted Nd–Fe–B magnetic nanoparticles with enhanced magnetic properties. NdxFe95-xB5 (15≤ x≤ 40) and Nd35-yDyyFe60B5 (0≤ y ≤8) magnetic nanoparticles were synthesised using a hydrothermal method, followed by a reduction-diffusion annealing process. We carried out a detailed experimental study of the effects of Nd content and Dy substitution on the phase assemblage and magnetic properties in the two systems. The results indicated that the coercivity of the Nd–Fe–B powders increased with increasing Nd content, and the maximum coercivity measured was 262.5 kA/m for Nd40Fe45B5 (by weight percentage). Conversely, the saturation magnetisation decreased with increasing Nd content. When the addition of Dy was less than 8 wt%, both the coercivity and the saturation magnetisation varied monotonically with the amount of Dy added, and a coercivity of 548.9 kA/m was measured for Nd27Dy8Fe60B5. The results show that hydrothermal method followed by a reduction-diffusion process is simple and economical in preparing Dy-substituted Nd2Fe14B magnetic nanoparticles, and the controllable and enhanced magnetic properties can be realised by simply adjusting the ratio of raw materials. This is also a good complement to the preparation of Nd–Fe–B nanoparticles by chemical methods.

Effect of Dy doping on the crystal orientation, microstructure, and electrical properties of PDZT thin films prepared by sol–gel method

Dysprosium-doped lead zirconate titanate thin films (PbDyx(Zr0.40Ti0.60)1−(3x/4)O3) (x = 0%, 1%, 2%, 3%, 4%, 5%), abbreviated as PDZT, were prepared by sol–gel method. The effects of Dy doping on the crystal orientation, microstructure, and electrical properties of lead zirconate titanate (PZT) films were studied. X-ray diffraction (XRD) analysis shows that PDZT thin films with Dy concentration less than 3% exhibit (111) preferred orientation, and the samples doped with 3%, 4%, and 5% show (100) preferred orientation. Scanning electron microscope (SEM) analysis results show that all samples exhibit dense perovskite structure. With the increase of doping content, the electrical properties of PDZT films show a trend of first increasing and then decreasing. An enhanced residual polarization strength of 60.89 μC/cm2 and an improved relative dielectric constant of 943.1 at 0.1 kHz are obtained in 2% doped PDZT film. Moreover, the PZT film with 2% Dy doped also exhibits a significantly reduced leakage current density.

Evidence of Weak Ferromagnetism, Space Charge Polarization, and Metal to Insulator Transition in Dy-Doped CaMnO3

The effect of Dy doping on CaMnO3 (CDMO) has been thoroughly investigated. The room-temperature structure, low-temperature magnetic transitions, and high-temperature electrical properties of CDMO were studied using X-ray diffraction, magnetization, and dielectric techniques. The CDMO exhibits an orthorhombic structure with Pnma symmetry. The low-temperature magnetic susceptibility data show the ferromagnetic domains embedded in the antiferromagnetic structure (G-type), and it confirms the Neel temperature (TN) approximately 55 K. Temperature-dependent dielectric data measured using a few selected frequencies show a high dielectric constant ~ 29,108,808 at 1 kHz. The presence of a high dielectric constant at the lower frequency side can be attributed to the space charge polarization (SCP) and compositional disorder (heterogeneity) in the compounds. The impedance cole-cole plot shows a depressed semicircle; mathematically these data were fitted by the Kohlrausch-Williams-Watt model. From this model obtained two mechanisms: (i) the electric modulus divulges the CDMO ceramic tails the Non-Debye type of relaxation and (ii) the electric modulus peak shifting evidence the charge carrier mobility from long range to short range. High-temperature dielectric, resistivity, and conductivity data show a clear anomaly around 461 K, owing to metal to insulator transition.