The Effect of α-Al2O3 Composite on Energy Storage Characteristics of the Orthogonal Phase PLZST Antiferroelectric Ceramics

The effect of (1-x)(Pb0.97La0.02)(Zr0.675Sn0.285Ti0.04)O3-xAl2O3, with x=0~0.04, 0.08, 0.10 composite ceramic samples was studied. In this experiment, the PLZST powder was pre-fired to obtain the perovskite structure, and then combined with α-Al2O3 to increase the BDS of the ceramic. The test results show that the composite thick film samples are all perovskite orthorhombic phases, and Al2O3 is mainly filled in the grain gaps with a flaky structure. A proper content of composite Al2O3 can increase the density of ceramics. With x=0.02, the maximum value of BDS is 25.27 kV/mm, which is 60% higher than pure PLZST material, and the releasable energy storage density also reaches a maximum of 2.95 J/cm³. After the composite amount exceeds 0.03, the saturation polarization intensity decreases significantly. The energy storage efficiency of each sample is generally not high, all of which are less than 65%.

Comprehensive investigation on RF/analog parameters in ferroelectric tunnel FET

In this paper, the effect of ferroelectric layer thickness (tFE), coercive field (Ec), remnant polarization (Pr), and saturation polarization (Ps) on transfer characteristic is highlighted for a Ferroelectric Tunnel FET (Fe-TFET) through a commercial TCAD simulator. Further, we have reported the RF/analog parameters like transconductance (gm), output conductance (gd), gain (gm/gd), gate capacitance (Cgg), and cut off frequency (ft) for wide range of FE parameters in Fe-TFET. Improved RF/analog performance and transfer characteristic are obtained for low value of tFE, Pr, Ec, whereas, these behavior is degraded at high value of Ps.

Manganese doping for enhanced magnetic brightening and circular polarization control of dark excitons in paramagnetic layered hybrid metal-halide perovskites

Materials combining semiconductor functionalities with spin control are desired for the advancement of quantum technologies. Here, we study the magneto-optical properties of novel paramagnetic Ruddlesden-Popper hybrid perovskites Mn:(PEA)2PbI4 (PEA = phenethylammonium) and report magnetically brightened excitonic luminescence with strong circular polarization from the interaction with isolated Mn2+ ions. Using a combination of superconducting quantum interference device (SQUID) magnetometry, magneto-absorption and transient optical spectroscopy, we find that a dark exciton population is brightened by state mixing with the bright excitons in the presence of a magnetic field. Unexpectedly, the circular polarization of the dark exciton luminescence follows the Brillouin-shaped magnetization with a saturation polarization of 13% at 4 K and 6 T. From high-field transient magneto-luminescence we attribute our observations to spin-dependent exciton dynamics at early times after excitation, with first indications for a Mn-mediated spin-flip process. Our findings demonstrate manganese doping as a powerful approach to control excitonic spin physics in Ruddlesden-Popper perovskites, which will stimulate research on this highly tuneable material platform with promise for tailored interactions between magnetic moments and excitonic states.

Production and Properties of High Entropy Carbide Based Hardmetals

Dense, high-entropy carbide cobalt-bonded hardmetals with two different compositions, namely (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co and (Ta-Ti-Nb-V-W)C-19.2 vol% Co, were successfully manufactured by gas pressure sintering (SinterHIP) at 1400 °C and 100 bar Ar pressure. The microstructure of these hardmetals consists of a rigid skeletal carbide phase embedded in a tough Co binder phase. EDS mappings showed that the high-entropy carbide phase did not decompose and that a typical hardmetal microstructure was realized. Only in the case of the (Hf-Ta-Ti-Nb-V)C-Co hardmetal was some undissolved TaC and HfO2, as well as some clustered vanadium titanium carbide phase, found, resulting in a split-up of the HEC phase into two very similar HEC phases. This resulted in a reduced hardness to fracture toughness ratio for this composition. Measurements of magnetic saturation polarization showed values between 57.5% and 70% of theoretical magnetic saturation polarization, indicating marginal dissolution of the carbide-forming metal elements in the binder phase. The hardness value HV10 for (Hf-Ta-Ti-Nb-V)C-19.2 vol% Co was 1203 HV10 and 1432 HV10 for (Ta-Ti-Nb-V-W)C-19.2 vol% Co.

A CHEMICAL ROUTE TO THE SYNTHESIS OF Bi1-xMgxFeO3 (x=0.1 and x=0.07) NANOPARTICLE WITH ENHANCED ELECTRICAL PROPERTIES AS MULTIFERROIC MATERIAL

Bismuth ferrite (BiFeO3) is one of multiferroic material group, but it is difficult to produce BiFeO3 in single phase as multiferroic material because it occurs leakage of current arising from non stoichiometric. So, to minimize it, it has already been engineering processed to synthesis BiFeO3 doped by Mg to produce Bi0.9Mg0.1FeO3 and Bi0.93Mg0.07FeO3. It used sol-gel method to produce the ceramics. The result of TGA/DTA(Thermo Gravimetric Analysis/Differential Thermal Analysis) test shows that the temperature of calcination is about of 150 and 175oC and temperature of sintering is about of 650oC. Characterization of the powder has already been done by using X-Ray Diffraction (XRD) test and electrical properties test. The results of XRD test show that the powder of Bi0.9Mg0.1FeO3has minimum impurities with total oxide of 6.9% (bismite 3.5% and silenite 3.4%) at calcination temperature of 175oC for 4 hours and sintering at 650oC for 6 hours. Meanwhile at same parameter, Bi0.93Mg0.07FeO3 has more oxide phases with total oxide of 14.5% which consists of silenite (2.5%) and Bi2O4 (12%). Presence of oxide phases could cause leakage of current decreasing electrical properties. The values of electrical saturation polarization for ceramic having minimum total oxide (Bi0.9Mg0.1FeO3) is higher than ceramic having more oxide (Bi0.93Mg0.07FeO3). The value of electric saturation polarization for Bi0.9Mg0.1FeO3 is of 0.26 kv/cm and for Bi0.93Mg0.07FeO3 is of 0.11 kV/cm.

Influence of Isothermal Heating on the Curie Temperature of FeCoB Bulk Amorphous Alloy

The article presents the results of research on the thermal treatment of amorphous alloys. As part of the work, an alloy with a chemical composition Fe63Co8Y8W1B20 was produced by rapid cooling. The method used to aspirate the liquid alloy into the copper mold was used. The produced material was subjected to annealing at 940K for 10 minutes. The alloy, after solidification and after heat treatment, was subjected to structure testing by means of X-ray diffraction. The soaking process led to the partial crystallization of the amorphous precursor. Using the Faraday magnetic balance, curves of the magnetic saturation polarization as a function of temperature were recorded, on the basis of their analysis, the Curie temperature of the produced materials was determined. Using the vibration magnetometer, the primary curves of magnetization and static magnetic hysteresis loops were measured. The alloy after the soaking process was characterized by higher Curie temperature and magnetically hard properties. The test results confirm the possibility of modifying the magnetic properties of high-temperature alloys through a suitably designed heat treatment.

Multiferroicity in the YFeO3 crystal

In this paper, orthoferrite YFeO3 was synthesized by hydrothermal method. The space group of YFeO3 is Pnma and the spin state of [Formula: see text] ion is low spin (LS). The YFeO3 crystal exhibits a weak antiferromagnetic behavior by magnetic measurement. For the electrical polarization measurement, micron-scale Pt electrodes were deposited on the both sides of the YFeO3 crystal by FIB-induced deposition. The saturation polarization value is 0.1994[Formula: see text][Formula: see text]C/cm2 at room temperature. The crystal exhibits ferroelectric behavior through the Dzyaloshinskii–Moriya interaction induced by additional spin canting of the antiferromagnetic ordering. This work may be applied to further study of the multiferroicity in rare-earth orthoferrites RFeO3.

ENHANCED FERROELECTRICITY AND FERROMAGNETISM OF (Y, Ni) CO-DOPED BiFeO3 MATERIALS

In this study, multiferroicMultiferroic Bi1-xYxFe0.975Ni0.025O3 (x = 0.00, 0.05, 0.10, and 0.15) called as (Y, Ni) co-doped BiFeO3 materials were synthesized by a sol-gel method. and characterized by X-ray diffraction diagrams and(XRD), energy-dispersive X-ray (EDX) and vibrating sample magnetization (VSM) measurements demonstrated. The result showed that Bi1-xYxFe0.975Ni0.025O3all investigated materials waspresent a single phase of the perovskite-type rhombohedral structure. Ferromagnetism and ferroelectricity of the Bi1-xYxFe0.975Ni0.025O3 materials have been investigated. Results showed that the co-doping by (Y, Ni) for (Bi, Fe) have affected in enhancing by the (Y, Ni) co-doping, as a result the ferroelectric polarization and magnetization of BiFeO3. The magnetic characterization indicated that the ferromagnetic behavior wasthe initial BiFeO3 materialwere enhanced with increasing concentration of Y3+ for (Y, Ni) co-substituted of BiFeO3. Which could beion. It is attributed to the defferentdifference of the magnetic momentmoments of Ni2+ and Fe3+, and+ ions, as well as the Y3+-Fe3+,+ and Y3+-Ni2+ super-exchange interaction. Theinteractions. The characteristics of the investigated materials, such as remanent magnetization (Mr), saturation magnetization (Ms), remanent polarization (2Pr) and saturation polarization (2Ps) continuously increase upon increasing in the range of x from 0.00 to 0.15. When x = 0.15, the values of Mr and Ms are 0.078 and 0.794 emu/g, respectively. The values of 2Pr and 2Ps are 16.58 and 27.99 µC/cm2, respectively. Origin of ferromagnetic and ferroelectric properties of Bi1-xYxFe0.975Ni0.025O3 materials will be discussed in this paper.