scholarly journals Dielectric, electrical conduction and magnetic properties of multiferroic Bi0.8Tb0.1Ba0.1Fe0.9Ti0.1O3 perovskite compound

2017 ◽  
Vol 07 (05) ◽  
pp. 1750034 ◽  
Author(s):  
Poonam Kumari ◽  
Radheshyam Rai ◽  
Seema Sharma ◽  
M. A. Valente
Keyword(s):  
Magnetic Properties ◽  
Perovskite Phase ◽  
Impedance Analysis ◽  
Hexagonal Structure ◽  
Nyquist Plot ◽  
Magnetic Studies ◽  
Electrical And Magnetic Properties ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Magnetization Field

This work focuses on the structural, electrical and magnetic properties of Bi[Formula: see text]Tb[Formula: see text]Ba[Formula: see text]Fe[Formula: see text]Ti[Formula: see text]O3 ceramics, fabricated by solid state reaction procedure. XRD forms of the samples at RT exhibited perovskite phase through the hexagonal structure at room temperature. Dielectric studies of the materials with frequency at different temperatures (25–400[Formula: see text]C) exhibit two dielectric anomalies, first at 175[Formula: see text]C (ferroelectric–ferroelectric transition) and second at around 320[Formula: see text]C (ferroelectric–paraelectric transition). The Curie temperature moved towards the low side temperature with the increase in frequency. The less value of activation energy got for these samples could be attributed to the influence of electronic contribution to the conductivity. A significant change in the magnetic studies was observed for Bi[Formula: see text]Tb[Formula: see text]Ba[Formula: see text]Fe[Formula: see text]Ti[Formula: see text]O3 ceramic. The impedance analysis confirms the non-Debye type nature of the ceramic and relaxation frequency moved to a higher temperature. The Nyquist plot and conductivity studies showed the NTCR behavior of samples. The highest magnetization field was found at temperature [Formula: see text]268.15[Formula: see text]C.

Cu-Doped SnO2 Nanoparticles: Synthesis and Properties

2019 ◽  
Vol 19 (11) ◽  
pp. 7139-7148 ◽  
Author(s):  
Suresh Sagadevan ◽  
Zaira Zaman Chowdhury ◽  
Mohd. Rafie Bin Johan ◽  
Fauziah Abdul Aziz ◽  
L. Selva Roselin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Band Gap ◽  
Chemical Constituents ◽  
Sno2 Nanoparticles ◽  
Impedance Analysis ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Electrical And Magnetic Properties ◽  
Different Temperatures ◽  
Co Precipitation

In this work, a simple, co-precipitation technique was used to prepare un-doped, pure tin oxide (SnO2). As synthesized SnO2 nanoparticles were doped with Cu2+ ions. Detailed characterization was carried out to observe the crystalline phase, morphological features and chemical constituents with opto-electrical and magnetic properties of the synthesized nanoparticles (NPs). X-ray diffraction analysis showed the existence of crystalline, tetragonal structure of SnO2. Both the sample synthesized here showed different crystalline morphology. The band gap energy (Eg) of the synthesized sample was estimated and it was found to decrease from 3.60 to 3.26 eV. The band gap energy reduced due to increase in Cu2+ dopant amount inside the SnO2 lattice. Optical properties were analyzed using absorption spectra and Photoluminescence (PL) spectra. It was observed that Cu2+ ions incorporated SnO2 NPs exhibited more degradation efficiencies for Rhodamine B (RhB) dye compared to un-doped sample under UV-Visible irradiation. The dielectric characteristics of un-doped, pure and Cu2+ incorporated SnO2 nanoparticles were studied at different frequency region under different temperatures. The ac conductivity and impedance analysis of pure and Cu2+ incorporated SnO2 nanoparticles was also studied. The magnetic properties of the synthesized samples were analysed. Both the sample showed ferromagnetic properties. The research indicated that the Cu2+ ions doping can make the sample a promising candidate for using in the field of optoelectronics, magneto electronics, and microwave devices.

scholarly journals Dielectric, ferroelectrics properties and impedance spectroscopy analysis of the [(Na0.535K0.480)0.966Li0.058](Nb0.90Ta0.10)O3-based lead-free ceramics

2015 ◽  
Vol 05 (01) ◽  
pp. 1550007 ◽  
Author(s):  
M. Saidi ◽  
A. Chaouchi ◽  
S. D'Astorg ◽  
M. Rguiti ◽  
C. Courtois
Keyword(s):  
Complex Impedance ◽  
Negative Temperature ◽  
Impedance Analysis ◽  
Xrd Analysis ◽  
Ac Impedance ◽  
Nyquist Plot ◽  
X Ray Diffraction ◽  
Complex Impedance Analysis ◽  
Lead Free Ceramics ◽  
Different Temperatures

Polycrystalline of [( Na 0.535 K 0.480)0.966 Li 0.058] (Nb 0.90 Ta 0.10) O 3 samples were prepared using the high-temperature solid-state reaction technique. X-ray diffraction (XRD) analysis indicates the formation of a single-phase with orthorhombic structure. AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures. The AC impedance studies revealed the presence of grain effect, from 425°C onwards. Complex impedance analysis indicated non-Debye type dielectric relaxation. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) characteristic of NKLNT. The AC conductivity results were used to correlate with the barrier hopping (CBH) model to evaluate the binding energy (Wm), the minimum hopping distance (R min ), the density of states at Fermi level (N(Ef)), and the activation energy of the compound.

scholarly journals Effect of Process Parameter Optimization in Reducing Sintering Temperature in the Synthesis and Characterization of Ba(Zn1/3Nb2/3)O3

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
P. K. Bajpai ◽  
K. N. Singh
Keyword(s):  
Perovskite Phase ◽  
Impedance Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Microwave Dielectric ◽  
Pure Perovskite Phase ◽  
Higher Temperature ◽  
Ac Conduction

Controlling the cooling rate during calcination and sintering, phase pure perovskite Ba(Zn1/3Nb2/3)O3 has been prepared by simple solid state reaction route with density >93% at relatively low sintering of 1175°C making it compatible for microwave dielectric applications. The samples are characterized by X-ray diffraction analysis and scanning electron microscopy. The X-ray diffraction shows pure perovskite phase with cubic structure. The lattice constants were obtained a = 4.1032 Å. Detailed studies of ε′ and ε′′ show that the compound exhibits dielectric anomaly at 430°C. Material shows distributed relaxation at higher temperature. Impedance analysis revealed that the impedance is mainly due to the grains. AC conduction activation energies are estimated from Arrhenius plots, and conduction mechanism is discussed.

scholarly journals Monte Carlo and Experimental Magnetic Studies of Molecular Spintronics Devices

NANO ◽  
2015 ◽  
Vol 10 (04) ◽  
pp. 1550056 ◽  
Author(s):  
Pawan Tyagi ◽  
Christopher D'Angelo ◽  
Collin Baker
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Coupling Effect ◽  
Experimental Studies ◽  
Magnetic Tunnel Junction ◽  
Magnetic Interactions ◽  
Magnetic Studies ◽  
Magnetic Molecules ◽  
Wide Range ◽  
Different Temperatures

Molecule-based spintronics devices (MSDs) are highly promising candidates for discovering advanced logic and memory computer units. An advanced MSD will require the placement of paramagnetic molecules between the two ferromagnetic (FM) electrodes. Due to extreme fabrication challenges, only a couple of experimental studies could be performed to understand the effect of magnetic molecules on the overall magnetic and transport properties of MSDs. To date, theoretical studies mainly focused on charge and spin transport aspects of MSDs; there is a dearth of knowledge about the effect of magnetic molecules on the magnetic properties of MSDs. This paper investigates the effect of magnetic molecules, with a net spin, on the magnetic properties of 2D MSDs via Monte Carlo (MC) simulations. Our MC simulations encompass a wide range of MSDs that can be realized by establishing different kinds of magnetic interactions between molecules and FM electrodes at different temperatures. The MC simulations show that ambient thermal energy strongly influenced the molecular coupling effect on the MSD. We studied the nature and strength of molecule couplings (FM and antiferromagnetic) with the two electrodes on the magnetization, specific heat and magnetic susceptibility of MSDs. For the case when the nature of molecule interaction was FM with one electrode and antiferromagnetic with another electrode the overall magnetization shifted toward zero. In this case, the effect of molecules was also a strong function of the nature and strength of direct coupling between FM electrodes. In the case when molecules make opposite magnetic couplings with the two FM electrodes, the MSD model used for MC studies resembled with the magnetic tunnel junction based MSD. The experimental magnetic studies on these devices are in agreement with our theoretical MC simulations results. Our MC simulations will enable the fundamental understanding and designing of a wide range of novel spintronics devices utilizing a variety of molecules, nanoclusters and quantum dots as the device elements.

scholarly journals High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C)/Fe Trilayer Thin Films

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Anabil Gayen ◽  
Barnali Biswas ◽  
Akhilesh Kumar Singh ◽  
Padmanapan Saravanan ◽  
Alagarsamy Perumal
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
High Temperature ◽  
Exchange Coupling ◽  
High Performance ◽  
Interlayer Exchange Coupling ◽  
Magnetic Studies ◽  
Different Temperatures ◽  
Interlayer Exchange ◽  
Hard Magnetic Properties

We report the investigation of temperature dependent magnetic properties of FePt and FePt(30)/M(Cu,C)/Fe(5) trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures.L10ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5)/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

Synthesis, structure, electrical and magnetic properties of the new non-stoichiometric perovskite phase, Ca2MnNbOγ

1998 ◽  
Vol 8 (11) ◽  
pp. 2515-2520 ◽  
Author(s):  
Angela Kruth ◽  
Mitsuharu Tabuchi ◽  
Ulrich Guth ◽  
Anthony R. West
Keyword(s):  
Magnetic Properties ◽  
Perovskite Phase ◽  
Electrical And Magnetic Properties

scholarly journals IMPEDANCE SPECTROSCOPY AND AC CONDUCTIVITY STUDIES OF FERROELECTRIC (K0.5Na0.5)NbO3 CERAMICS

2011 ◽  
Vol 01 (03) ◽  
pp. 351-356 ◽  
Author(s):  
P. PALEI ◽  
P. KUMAR
Keyword(s):  
Ac Conductivity ◽  
Single Phase ◽  
Perovskite Phase ◽  
Impedance Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Higher Temperature

Lead free (K0.5Na0.5)NbO3 (KNN) ceramics were prepared by conventional solid state reaction route. For single perovskite phase formation, calcination temperature was optimized at 850°C for 6 h, whereas for dense morphology the sintering of the ceramic was carried out at 1120°C for 4 h. X-ray diffraction XRD analysis confirmed the formation of single phase with orthorhombic structure at room temperature. Impedance analysis and AC conductivity studies of the KNN sample was carried out in the temperature range of 703–773 K. Impedance study showed the increase in conducting behavior at higher temperature. The temperature dependence of AC conductivity indicated that the conduction process is due to doubly ionized oxygen vacancies in the higher temperature region.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Structural and Magnetic Hysteresis Properties of Co-Zr Substituted Hexagonal Barium Ferrites

2015 ◽  
Vol 7 (1) ◽  
pp. 1346-1351
Author(s):  
Ch.Gopal Reddy ◽  
Ch. Venkateshwarlu ◽  
P. Vijaya Bhasker Reddy
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Magnetic Hysteresis ◽  
Grain Morphology ◽  
Hexagonal Structure ◽  
Ion Composition ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
Barium Ferrites ◽  
Xrd Patterns

Co-Zr substituted M-type hexagonal barium ferrites, with chemical formula BaCoxZrxFe12-2xO19 (where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), have been synthesized by double sintering ceramic method. The crystallographic properties, grain morphology and magnetic properties of these ferrites have been investigated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirm the single phase with hexagonal structure of prepared ferrites. The magnetic properties have been investigated as a function of Co and Zr ion composition at an applied field in the range of 20 KOe. These studies indicate that the saturation magnetization (Ms) in the samples increases initially up to the Co-Zr composition of x=0.6 and decreases thereafter. On the other hand, the coercivity (Hc) and Remanent magnetization (Mr) are found to decrease continuously with increasing Co-Zr content. This property is most useful in permanent magnetic recording. The observed results are explained on the basis of site occupation of Co and Zr ions in the samples.

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