The structural characteristics and microwave dielectric properties of SrBi
2
TeO
7
ceramics intended for low-temperature co-fired ceramic (LTCC) applications were investigated. Comprehensive analyses ...were conducted using x-ray diffraction, structural refinement, transmission electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. The findings demonstrated that SrBi
2
TeO
7
ceramics possess a pure cubic structure. Scanning electron microscopy characterizes the grain microstructure, revealing a relative density of 95.5% for SrBi
2
TeO
7
ceramic. Optimal microwave dielectric properties were achieved for SrBi
2
TeO
7
ceramics calcined at 765°C, displaying a relative permittivity (
ε
r
) of 24.96, a
Q
×
f
value of 25,898 GHz (
f
= 6.6 GHz), and a temperature coefficient of resonant frequency (
τ
f
) of –80.7 ppm/°C. The combination of low sintering temperature and minimal dielectric loss renders these ceramics advantageous for utilization in LTCC materials.
An appropriate amount of Zn-ions are incorporated into the high Curie temperature bismuth layer-structure ferroelectric material to fabricate Sr0.2Na0.4Pr0.4Bi4Ti4O15:xwt%ZnO; (SNPBT:xZn), with x = ...0, 0.10, 0.15, and 0.20 ceramic series to investigate the magnetic, ferroelectric, and energy storage efficiency and piezoelectric properties. Pure SNPBT and SNPBT:xZn ceramics have maintained their structure even after the intercalation of Zn-ions at the lattice sites of SNPBT. The addition of ZnO in SNPBT has improved the multifunctional properties of the material at x = 0.15. At room temperature, SNPBT:0.15Zn has shown a high relative density of 96%, exhibited weak ferromagnetic behavior along with a low saturation magnetization (Ms) of 0.028 emu/g with a low coercive field of 306 Oe, a high remnant polarization (Pr) of 9.04 µC/cm2, a recoverable energy density (Wrec) of ~0.5 J/cm3, an energy conversion efficiency (η) of ~41%, a high piezoelectric co-efficient (d33) of 21 pC/N, and an impedance of 1.98 × 107 Ω, which are much improved as compared to pure SBT or pure SNPBT ceramics. Dielectric Constant (ɛr) versus temperature plots present the sharp peak for SNPBT:0.15Zn ceramic at a Curie temperature (TC) ~ 605 °C, confirming the strong ferroelectric nature of the ceramic. Moreover, SNPBT:0.15Zn ceramic has shown strong, piezoelectric, thermally stable behavior, which remains at 76% (16 pC/N) of its initial value even after annealing at 500 °C. The achieved results clearly indicate that SNPBT:0.15Zn ceramic is a promising candidate for future wide-temperature pulse power applications and high-temperature piezoelectric devices.
SrBi
4
Ti
4
O
15
is a four-layer member of the Aurivillius compound and reported to have photocatalyst properties with a band gap energy of 3.0 eV (420 nm). Doped with metal elements is a strategy to ...reduce the band gap energy of photocatalyst material in order to increase its utilization under a wider energy spectrum of visible light. Here in, Fe-doped SrBi
4
Ti
4
O
15
was synthesized using Na
2
SO
4
/K
2
SO
4
molten salt method. The diffractogram revealed that all samples were successfully synthesized in the
A
2
1
am
space group with no impurity phase. Raman spectra confirmed the existence of a typical Raman vibration peak for a four-layer Aurivillius family compound and the local changes in TiO
6
structure due to Fe dopant mirrored by vibration mode at ~ 559 cm
−1
. SEM images showed that the all samples morphology is plate-like however, the particle size of Fe-doped SrBi
4
Ti
4
O
15
is bigger than the undoped compound. Meanwhile, the UV–Vis DRS spectra revealed that Fe dopant could effectively reduce the band gap energy resulting in obvious red shift absorption to the wider visible light region (530–705 nm).
For the proposed work, the electrical properties of metal–ferroelectric–insulator–silicon (MFeIS) capacitors with Sr
0.8
Bi
2.2
Ta
2
O
9
(SBT) ferroelectric film deposited on HfO
2
/Si substrate have ...been investigated. The SBT film was deposited by RF sputtering and HfO
2
film by plasma-enhanced atomic layer deposition (PEALD). The structural characteristic of the deposited ferroelectric and dielectric films was obtained using X-ray diffraction and multiple angle ellipsometric analysis. XRD results indicate the polycrystalline and perovskite structure of the SBT film and amorphous structure of the HfO
2
film annealed at different temperatures. SBT film deposited on the silicon substrate and annealed at 500 °C shows the maximum refractive index of 3.46 with the maximum grain size of 32 nm. Metal/ferroelectric/silicon (MFeS), metal/ferroelectric/metal (MFeM), metal/insulator/silicon (MIS) and metal/ferroelectric/insulator/silicon (MFeIS) structures were fabricated to obtain the electrical and ferroelectric properties. MFeIS structure with 10 nm buffer layer shows the improved memory window of 5 V as compared to the 3.07 V in the MFeS structures. MFeI
(10 nm)
S structure even shows endurance higher than 10
12
read/write cycles and data retention for more than 8 h.
•Co-precipitation-hydrothermal synthesized of SrBi2Nb2O9 was described.•Structural characterization was reported.•Dielectric properties at room temperature of proposed material can match them up with ...SrBi2Nb2O9 prepared via solid state reaction method.
Strontium Bismuth Niobate (SrBi2Nb2O9) was synthesized by co-precipitation-hydrothermal method. Precipitation step was first carried out at room temperature at which the powder was prepared from aqueous solution of Bi(NO3)3, Sr(NO3)2 and Nb2O5. Then the process is completed by hydrothermal treatment. The compound crystallized in the orthorhombic structure. The characteristic bands, at approximately 619cm−1 and 816cm−1 were observed. The grain size is around 1µm. The dielectric properties at room temperature show low loss values at higher frequencies which makes it suitable for ferroelectric random access memory applications.
We demonstrated the formation and reading of flexoelectrically-switched polarization nanobits in c-oriented, epitaxial layered-perovskite thin films. Highly c-oriented epitaxial SrBi2Nb2O9 (SBN) thin ...films were deposited on Nb-doped single crystal (100) SrTiO3 (Nb:STO) substrates via pulsed laser deposition (PLD) technology. X-ray diffraction (XRD) experiments, ferroelectric hysteresis loops, leakage current curves, and fatigue characteristics revealed that these films preferred in-plane oriented domains. Flexoelectrically switched polarization nanobits with horizontally switched domains were formed within an upwardly switched domain of the c-oriented epitaxial SBN thin film by applying external forces orthogonal to the surface. In particular, flexoelectrically switched polarization nanobits didn't have out-of-plane-oriented domains, reflecting the c-oriented nature of the Aurivillius SBN thin film.
•Switched ferroelectric polarization nanobits by flexoelectric force.•Highly c-oriented Aurivillius SBN thin films.•Crystallinity-dependent switching characteristics.
The present work investigates microstructural, structural, ferroelectric and dielectric properties of Holmium, Ho
3+
, doped SrBi
4
Ti
4
O
15
(SBT). Polycrystalline ceramics (SrBi
4-x
Ho
x
Ti
4
O
15
...SBHT, where x = 0, 0.02. and 0.03) were prepared by solid-state reaction method using high energy planetary ball mill. The surface morphology of all samples displayed dense microstructure and average grain size decreased with Holmium content increase. The XRD results of samples confirmed a single phase of SBT with orthorhombic crystal structure and a reduction in unit cell volume with the substitution of Holmium at B-site. The improvement in the structural and microstructural properties greatly enhanced the electric properties of SBHT. SBHT (x = 0.02) sample showed the improved ferroelectric properties (remnant polarization P
r
= 1.63 μC/cm
2
and Coercive field E
c
= 0.51 kV/cm) making them suitable for ferroelectric applications. High Curie temperature (T
C
= 626 °C), elevated dielectric constant (ε
r
= 236) and low loss (tanδ = 0.062) are obtained with the substitution of Ho (for x = 0.03) at B- site of SBT. These ceramics have high T
C
and improved thermal stability which makes these apt for the applications in high temperature sensors.
•Ho-doped SrBi2Nb2O9 ceramics were synthesized by the conventional solid-state reaction method.•Samples were characterized by XRD, FTIR and SEM.•The dielectric and electrical properties were ...investigated.
SrBi2-xHoxNb2O9 (0 ≤ x ≤ 0.5) ceramics were prepared through the conventional solid state route. The materials have been characterized by XRD, FTIR and SEM. All compounds were pure and well crystallized. In FTIR spectroscopy, the spectral patterns of the crystal structures of these polyphases are unique and smoothly different from each other. The grains were prone to become spherical with increasing x. Dielectric and electrical properties of these materials as a function of temperature at different frequencies have been carried out. The dielectric constant and dielectric loss were found to decrease with an increase of the holmium concentration at room temperature. Reaching up to x = 0.4 and x = 0.5, the diffusivity increases, leading to the occurrence of relaxor behavior. 20–30 at.% Ho doping on the Bi-site can fill up the oxygen vacancies and decrease the AC conductivity. However, at higher doping levels greater than 40% holmium oxide, the AC conductivity is found to increase.
A p-channel metal-ferroelectric-insulator-silicon field-effect transistor (FET) with a 300-nm-thick SrBi 2 Ta 2 O 9 (SBT) ferroelectric film and a 10-nm-thick HfTaO layer on silicon substrate was ...fabricated and characterized. The device shows a nearly unchanged memory window of about 0.9 V after a 2 × 10 11 -cycles fatigue test, an on/off current ratio of more than 10 7 , and a field-effect mobility of approximately 42 cm 2 /V · s. Moreover, a drain-current on/off ratio as high as 10 5 was obtained with a fixed gate voltage of 2.5 V after over a 10 5 -s elapsed time without any obvious degradation. These results may suggest that the Pt/SBT/HfTaO/Si FET is suitable for high-performance ferroelectric memory.
Distanciranje Crne Gore od državne zajednice sa Srbijom otpočinje krajem 1990-ih, u vremenu u kojem je promotorima srpske velikodržavne ideologije izrazito sužen prostor da takvo što spriječe silom. ...Stoga se posegnulo za drugim instrumentima usmjerenima na uništenje ili minoriziranje identitetne konstrukcije nacionalnog crnogorstva među pravoslavnom populacijom Crne Gore te na njezino nadomještanje nacionalnim srpstvom, uz ispravnu procjenu da je nacionalno crnogorstvo glavna snaga u samosvojnom uobličavanju Crne Gore. Takva kojoj je najbolje suprotstaviti od dijela nekadašnjih nacionalnih Crnogoraca oblikovani »srpski narod u Crnoj Gori« kako bi se tu zemlju zadržalo, odnosno, nakon postizanja neovisnosti 2006. vratilo pod srpsko državno okrilje. U ovome radu dat ćemo prikaz povijesnog razvoja koji je omogućio da prikazani vid srpskog velikodržavnog djelovanja u Crnoj Gori bude relativno uspješan, a zatim i uvid u postojeće političke i nacionalne-demografske suodnose u toj zemlji. Ujedno, analizirat ćemo uzroke koji utječu na to da se nacionalno crnogorstvo teško nosi s pokušajima vlastite identitetne destrukcije te istaknuti razloge zbog kojih bi u svojim naporima za samoodržanjem trebali dobiti sasvim konkretnu podršku regionalnih i euroatlantskih struktura.
The distancing of Montenegro from the state union with Serbia began in the late 1990s, a time when proponents of the Greater Serbian nationalist ideology had significantly limited capacity to prevent it by force. Therefore, they resorted to other instruments aimed at the destruction or marginalization of identity construction of Montenegrin nationalism among the Orthodox population of Montenegro, and its replacement with Serbian national identity. They correctly assessed that Montenegrin nationalism was the main force in shaping an independent Montenegro. To counter this, they used the “Serbian people in Montenegro” formed from a faction of former Montenegrin nationals, with the aim of retaining, and after achieving independence in 2006, also returning the country under Serbian state protection. This paper will provide an overview of the historical development that enabled this relatively successful implementation of the form of Serbian Greater nationalist activity in Montenegro, as well as an insight into the existing political and national-demographic inter-relations in the country. Additionally, we will analyze the factors that make it difficult for Montenegrin nationalism to cope with attempts of its own identity destruction, and emphasize the reasons why they should receive concrete support from regional and Euro-Atlantic structures in their self-preservation efforts.
