Effect of Nd Doping on Nanosized Mn-Zn Ferrite

Nanosized Mn-Zn ferrite doped with Nd (Mn_ 0.6Zn_ 0.4Nd_xFe_ 2-xO_4) were fabricated by hydrothermal precipitation route and studied by XRD, TEM, DSC and VSM. The effects of Nd doping on manganese zinc ferrites were discussed. The results show that the samples with a small amount of Nd doping are spinel crystal structure and uniformly nanosized particles with little aggregation. DSC analysis of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4Nd_ 0.06Fe_ 1.94O_4 samples both present two exothermic peaks ascribed to the redistribution of Mn 2+, Zn 2+ and Fe 3+ ions in the two sub-lattices (tetrahedral (A) and octahedral (B) sites), and the oxidation of Mn 2+-ions at higher temperatures respectively. The saturation magnetization (M_s) for Mn_ 0.6Zn_ 0.4Nd_xFe_ 2-xO_4 ferrites increase with (x) up to 0.06 and decrease for higher concentrations. And supermagnetic behavior was observed at 25 ℃ in the M-H loops of Mn_ 0.6Zn_ 0.4Fe_2O_4 and Mn_ 0.6Zn_ 0.4Nd_ 0.06Fe_ 1.94O_4 samples for their extremely small sizes.

High discharged energy density of polymer nanocomposites induced by Nd-doped BaTiO_(3)nanoparticles

A flexible polymer nanocomposite has been developed via introducing Nd-doped BaTiO_(3)nanoparticles into the poly(vinylidene fluoride).This nanocomposite delivers a discharged energy density up to 12.5 J/cm^(3)under an electric field of 420 kV/mmwith only a small loading of 1 vol.%Nd-BaTiO_(3).High discharged energy density,mechanical flexibility,light weight,ease fabrication and low cost makes it attractive for advanced microelectronics and electrical power systems.Our results demonstrate that ceramics with giant dielectric permittivity as viable fillers for polymer nanocomposite dielectrics with higher energy density.

Structure,defects,and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba_(4)Nd_(9.33)Ti_(18)O_(54)ceramics

Low-loss tungsten–bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation(5G)communication technology.In this work,a novel Al/Nd co-doping method of Ba_(4)Nd_(9.33)Ti_(18)O_(54)(BNT)ceramics with a chemical formula of Ba_(4)Nd_(9.33+z/3)Ti_(18−z)Al_(z)O_(54)(BNT–AN,0≤z≤2)was proposed to improve the dielectric properties through structural and defect modulation.Together with Al-doped ceramics(Ba_(4)Nd_(9.33)Ti_(18−z)Al_(4z/3)O_(54),BNT–A,0≤z≤2)for comparison,the ceramics were prepared by a solid state method.It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping.As the doping amount z increased,the relative dielectric constant(εr)and the temperature coefficient of resonant frequency(τf)of the ceramics decreased,and the Q×f values of the ceramics obviously increased when z≤1.5.Excellent microwave dielectric properties ofεr=72.2,Q×f=16,480 GHz,andτf=+14.3 ppm/℃were achieved in BNT–AN ceramics with z=1.25.Raman spectroscopy and thermally stimulated depolarization current(TSDC)technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics.It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies(VO××),demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.

Effect of Nd2O3 doping on the electrical properties of Ba0.96Ca0.04Ti0.90Sn0.10O3 ceramics

The Ba（0.96）Ca（0.04）Ti（0.90）Sn（0.10）O3-xNd2 O3（x = 0-0.08%） ceramics were prepared via traditional solid-state sintering method. The influences of Nd3＋ substitution on the phase structure, dielectric properties,piezoelectric and ferroelectric properties of the ceramics were investigated. All the samples possess pure BaTiO3-type perovskite structure. MPB with orthorhombic and tetragonal phase coexist at around x = 0.03-0.04. Nd^（3＋） doping decreases both Tc and T（O-T） to lower temperature. All the samples exhibit an intermediate state with the coexistence of ferroelectric and diffuse relaxor ferroelectric behavior with the addition of Nd^（3＋）. The electric properties of the ceramics were optimized at x = 0.03 with d33, Kp, εr and Pr values of 545 pC/N, 51.9%, 24,412 and 10.74 μC/cm^2.

Combustion synthesis, characterization and luminescence properties of barium aluminate phosphor

The blue-green emitting Eu2＋ and Nd3＋ doped polycrystalline barium aluminate （BaAI204：Eu2＋,Nd3＋） phosphor, was prepared by a solution-combustion method at 500 ℃without a post-annealing process. The characteristic variation in the structural and luminescence properties of the as-prepared samples was evaluated with regards to a change in the Ba/A1 molar ratio from 0.1：1 to 1.4：1. The morphologies and the phase structures of the products were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, while the optical properties were investigated using ultra-violet （UV） and photoluminescence （PL） spectroscopy, respectively. The XRD and TEM results revealed that the average crystallite size of the BaAl2O4：Eu2＋,Nd3＋ phosphor was about 70 urn. The broad-band UV-excited luminescence of the phosphors was observed at 2max=500 um due to transitions from the 4f^65d1 to the 4f7 configuration of the Eu2＋ ion. The PL results indicated that the main peaks in the emission and excitation spectrum of phosphor particles slightly shifted to the short wavelength due to the changes in the crystal field due to the structure changes caused by the variation in the quantity of the Ba ions in the host lattice.