Magnetoelectric properties of BST/LSMO particulate composites

2011 ◽  
Vol 1368 ◽  
Author(s):  
Juan Beltran-Huarac ◽  
R. Martinez ◽  
R. Palai
Keyword(s):  
Magnetic Fields ◽  
Composite Structures ◽  
Colossal Magnetoresistance ◽  
Relative Dielectric Constant ◽  
Dielectric Behavior ◽  
Dielectric Measurement ◽  
Particulate Composites ◽  
Low Frequencies ◽  
X Ray ◽  
Low Dielectric

ABSTRACTCurrently, ferroelectric and ferromagnetic particulate composites are receiving a great deal of interest due to their novel applications in microelectronic devices. Their excellent properties such as high relative dielectric constant, low dielectric loss, strong tunability, and ferromagnetism with colossal magnetoresistance can be controlled by manipulating both electric and magnetic fields. Ba0.7Sr0.3TiO3 /La0.67Sr0.33MnO3 (BST/LSMO) composite was prepared with 20:1 wt% by a high temperature solid-state reaction route. The X-ray diffraction (XRD) pattern confirmed the formation and the coexistence of both phases corresponding to BST and LSMO. High resolution field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) revealed a uniform distribution of the grain size throughout the surface of the sample and the presence of all the constituent elements with its esteemed reaction stoichiometry, respectively. In spite of the presence of both phases, only one transition peak was seen (50Hz-5MHz) around 295 K in dielectric measurement suggesting a nonlinear magnetoelectric coupling. The dielectric properties of BST/LSMO composite carried with different magnetic fields (0-1.7 T) show significant change in the BST dielectric behavior at low frequencies. The M-H curves at room temperature (RT) showed a drop in the saturation magnetization compared with pure LSMO is consistent with our composite structures.

Investigation of dielectric behavior of the PVC/BaTiO3 composite in low-frequencies

2018 ◽  
Vol 32 (09) ◽  
pp. 1850110 ◽  
Author(s):  
A. Berrag ◽  
S. Belkhiat ◽  
L. Madani
Keyword(s):  
Dielectric Properties ◽  
Dielectric Behavior ◽  
Index Formula ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Frequency Range ◽  
Low Frequencies ◽  
X Ray ◽  
Space Charges ◽  
Loss Index

Polyvinyl chloride (PVC) is widely used as insulator in electrical engineering especially as cable insulation sheaths. In order to improve the dielectric properties, polymers are mixed with ceramics. In this paper, PVC composites with different weight percentages 2 wt.%, 5 wt.%, 8 wt.% and 10 wt.% were prepared and investigated. Loss index ([Formula: see text]) and dielectric constant ([Formula: see text]) have been measured using an impedance analyzer RLC. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) have been used as characterization techniques. The incorporation of BaTiO3 does not modify the crystallinity and the morphology of the PVC but reduces the space charges, therefore the dielectric losses. The frequency response analysis has been followed in the frequency ranges (20–140 Hz and 115–1 MHz). Relaxation frequencies have been evaluated in each frequency range. Experimental measurements have been validated using Cole–Cole’s model. Experimental results show well that BaTiO3 as a filler improves the dielectric properties of PVC.

scholarly journals Influence of interface point defect on the dielectric properties of Y doped CaCu3Ti4O12 ceramics

2016 ◽  
Vol 06 (01) ◽  
pp. 1650009 ◽  
Author(s):  
Jianming Deng ◽  
Xiaojun Sun ◽  
Saisai Liu ◽  
Laijun Liu ◽  
Tianxiang Yan ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Earth Element ◽  
Solid State Reaction Method ◽  
Dielectric Behavior ◽  
Ccto Ceramic ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Low Frequencies ◽  
X Ray ◽  
Structure And Microstructure

CaCu3Ti[Formula: see text]YxO[Formula: see text] (0[Formula: see text]0.12) ceramics were fabricated with conventional solid-state reaction method. Phase structure and microstructure of prepared ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The impedance and modulus tests both suggested the existence of two different relaxation behavior, which were attributed to bulk and grain boundary response. In addition, the conductivity and dielectric permittivity showed a step-like behavior under 405[Formula: see text]K. Meanwhile, frequency independence of dc conduction became dominant when above 405[Formula: see text]K. In CCTO ceramic, rare earth element Y[Formula: see text] ions as an acceptor were used to substitute Ti sites, decreasing the concentration of oxygen vacancy around grain-electrode and grain boundary. The reason to the reduction of dielectric behavior in low frequencies range was associated with the Y doping in CCTO ceramic.

scholarly journals Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4017
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Ceramic Materials ◽  
Sintering Behavior ◽  
Terahertz Time Domain Spectroscopy ◽  
Very High Frequency ◽  
X Ray ◽  
Low Dielectric ◽  
Very High

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

scholarly journals Novel Polyimide/Copper-Nickel Ferrite Composites with Tunable Magnetic and Dielectric Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1646
Author(s):  
Corneliu Hamciuc ◽  
Mihai Asandulesa ◽  
Elena Hamciuc ◽  
Tiberiu Roman ◽  
Marius Andrei Olariu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Nickel Ferrite ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Broadband Dielectric Spectroscopy ◽  
Copper Nickel ◽  
Low Dielectric ◽  
Magnetic Remanence ◽  
Polyimide Matrix ◽  
Ferrite Composites

Heat-resistant magnetic polymer composites were prepared by incorporating cerium-doped copper-nickel ferrite particles, having the general formula Ni1-xCuxFe1.92Ce0.08O4 (x: 0.0, 0.3, 0.6, 1.0), into a polyimide matrix. The effects of particle type and concentration on the thermal, magnetic, and electrical properties of the resulting composites were investigated. The samples were characterized by FTIR, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, vibrating sample magnetometer, and broadband dielectric spectroscopy. The composites exhibited high thermal stability, having initial decomposition temperatures between 495 and 509 °C. Saturation magnetization (Ms), magnetic remanence (Mr), and coercivity (Hc) were found in range of 2.37–10.90 emu g−1, 0.45–2.84 emu g−1, and 32–244 Oe, respectively. The study of dielectric properties revealed dielectric constant values of 3.0–4.3 and low dielectric losses of 0.016–0.197 at room temperature and a frequency of 1 Hz.

Colossal Magnetoresistance in Thick La0.7Ca0.3MnO3 Films

1995 ◽  
Vol 384 ◽  
Author(s):  
Randolph E. Treece ◽  
P. Dorsey ◽  
M. Rubinstein ◽  
J. M. Byers ◽  
J. S. Horwitz ◽  
...  
Keyword(s):  
Colossal Magnetoresistance ◽  
Single Phase ◽  
Laser Deposition ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Post Deposition Annealing ◽  
X Ray ◽  
Mr Effect ◽  
Deposited Films ◽  
Post Deposition

ABSTRACTThick films (0.6 and 2.0 μm) of the colossal magnetoresistance (CMR) material, La0.7Ca0.3MnO3 (LCMO), have been grown by pulsed laser deposition (PLD). The films were grown from single-phase LCMO targets in 100 mTorr 02 pressures and the material deposited on (100) LaAlO3 substrates at deposition temperatures of 800°C. The deposited films were characterized by X-ray diffraction (XRD), magnetic field-dependent resistivity, and Rutherford backscattering spectroscopy (RBS). The LCMO films were shown by XRD to adopt an orthorhombic structure. Brief post-deposition annealing led to ~50,000% and ~12,000% MR effect in the 0.6 μm and 2.0 μm films, respectively.

ON THE DIELECTRIC BEHAVIOR OF LiCo3/5Fe2/5VO4 CERAMICS

2010 ◽  
Vol 24 (07) ◽  
pp. 665-670
Author(s):  
MOTI RAM
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Frequency Dependence ◽  
Chemical Method ◽  
Arrhenius Plot ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
Low Frequencies ◽  
Different Temperatures ◽  
Tan Δ

The LiCo 3/5 Fe 2/5 VO 4 ceramics has been fabricated by solution-based chemical method. Frequency dependence of the dielectric constant (εr) at different temperatures exhibits a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies indicates the dielectric anomalies in εr at Tc (transition temperature) = 190°C, 223°C, 263°C and 283°C with (εr) max ~ 5370, 1976, 690 and 429 for 1, 10, 50 and 100 kHz, respectively. Frequency dependence of tangent loss ( tan δ) at different temperatures indicates the presence of dielectric relaxation in the material. The value of activation energy estimated from the Arrhenius plot of log (τd) with 103/T is ~(0.396 ± 0.012) eV.

scholarly journals Single shot x-ray diffractometry in SACLA with pulsed magnetic fields up to 16 T

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Akihiko Ikeda ◽  
Yasuhiro H. Matsuda ◽  
Xuguang Zhou ◽  
Takeshi Yajima ◽  
Yuya Kubota ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Single Shot ◽  
Pulsed Magnetic Fields ◽  
X Ray

Edge Illumination X-Ray Phase Contrast Imaging and Ultrasonic Attenuation for Porosity Quantification in Composite Structures

2021 ◽  
Author(s):  
Dana Shoukroun ◽  
Sandro Olivo ◽  
Paul Fromme
Keyword(s):  
Carbon Fiber ◽  
Composite Structures ◽  
Phase Contrast ◽  
Ultrasonic Attenuation ◽  
Aerospace Industry ◽  
Composite Plates ◽  
Phase Contrast Imaging ◽  
Fiber Reinforced ◽  
Contrast Imaging ◽  
X Ray

Abstract Carbon fiber reinforced composites are widely used in the aerospace industry, due to their low weight and high strength. Porosity often occurs during the manufacturing of composite structures, which can compromise the structural integrity of the part and affect its mechanical properties. In the aerospace industry a typical requirement for structural components is for the porosity content to be kept below 2%. Non-destructive evaluation (NDE) techniques are used to estimate the porosity content in composite components, the most common being ultrasonic attenuation and X-ray computed tomography (CT). Planar Edge Illumination X-ray Phase Contrast Imaging (EI XPCI) was used to quantify the porosity content in woven carbon fiber reinforced composite plates with porosity ranging between 0.7% and 10.7%. A new metric was introduced, the standard deviation of the differential phase (STDVDP) signal, which represents the variation of inhomogeneity in the plates for features of a scale equal to or above the system resolution (here 12μm). The SDTVDP was found to have a very high correlation with porosity content estimated from matrix digestion and ultrasonic attenuation, hence providing a promising new methodology to quantify porosity in composite plates.

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