Structural, electrical and magneto-electric characteristics of complex multiferroic perovskite Bi0.5Pb0.5Fe0.5Ce0.5O3

2019

J Adv Ceram

Self Cite

The polycrystalline sample of a double perovskite, Sm 2 NiMnO 6 was synthesized by a solid-state reaction route. From the X-ray structural study, it is found that the structure of the material is monoclinic with lattice parameters: a = 4.1750(63) Å, b = 7.6113(63) Å, c = 5.9896(63) Å, and β = 112.70°. These parameters are very close to and consistent with those of such type of materials. The dielectric, impedance, AC conductivity, and electrical modulus properties of the sample were studied in the temperature range of 25-300 ℃ and the frequency range of 1 kHz-1 MHz. Typical relaxor behavior observed in the dielectric studies was confirmed by Vogel-Fulcher fitting. From the Nyquist plots, the temperature dependent contribution of grain and grain boundary effect was confirmed. The non-Debye type of relaxation was found using the complex impedance spectroscopy. The magnetic study revealed that the sample had paramagnetic behavior at room temperature. Magneto-electric (ME) coefficient was obtained by changing DC bias magnetic field. This type of lead-free relaxor ferroelectric compound may be useful for high-temperature applications.

Section: Impedance Spectroscopymentioning

confidence: 99%

Dielectric relaxation and magneto-electric characteristics of lead-free double perovskite: Sm2NiMnO6

Das

2019

J Adv Ceram

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“…The appearance of the temperature dependence of the relaxation phenomena is confirmed from the reduction of relaxation time with the rise in temper- (RQC)(RQC) 52.6 1.029 · 10 −6 1.410 · 10 −8 88.61 5.250 · 10 −14 5.250 · 10 −14 150 (RQC)(RQC)(RC) 1.08 · 10 9 1.650 · 10 −15 1.659 · 10 12 5.61 · 10 7 3.418 · 10 −2 5.250 · 10 −14 62. ature. Owing to the existence of immobile charges at low temperatures and imperfections/oxygen vacancies at higher temperatures, relaxation process occurs [35].…”

Section: Impedance Analysismentioning

confidence: 99%

Structure, dielectric and electrical properties of relaxor lead-free double perovskite: Nd2NiMnO6

Das

2019

PAC

In this paper, dielectric relaxor, impedance, AC conductivity and electrical modulus of double perovskite Nd 2 NiMnO 6 , prepared by a solid state reaction method and sintered at 1250°C, have been reported in the wide temperature (25-150°C) and frequency (1 kHz-1 MHz) ranges. From the preliminary X-ray structural analysis, it is found that the structure of the material is monoclinic. In the study of the temperature dependence of the dielectric constant, the relaxor behaviour of the material is observed. Such type of behaviour is explained by a modified Curie-Weiss and a Vogel-Fulcher law. By analysing Nyquist plots, the existence of grain and grain boundary effects is established. The non-Debye type of relaxation is investigated by the analysis of complex impedance and the modulus data. From the study of impedance data, it is found that the grain resistance is reduced with the increase in temperature indicating the existence of negative temperature coefficient of resistance (NTCR) behaviour in the material which also matches with temperature versus AC conductivity plots. From these results, it may be concluded that this compound may have extreme potential for different high temperature applications.

“…It is also prominent that with the increase in temperature the peak height decreases suggests that with the temperature rise, grain resistance reduces. This is because of the steady electrons (charges) at lower temperature and the creation of defects/oxygen vacancy at higher values of temperature [62].…”

Section: Frequency Dependence Of Z' and Z''mentioning

confidence: 99%

Studies of structural and electrical characteristics of multi-substituted Bi0.5Na0.5TiO3 ferroelectric ceramics

Arya

J Mater Sci: Mater Electron

2021

Self Cite

In this communication, preliminary structural and detailed electrical characteristics of the CaSnO3/CaSeO3 modified Bi0.5Na0.5TiO3 ceramics of a general chemical composition (1-2x) [Bi0.5Na0.5TiO3] + x (CaSnO3) + x (CaSeO3) with x= 0, 0.05, 0.10, 0.15, prepared by hightemperature solid-state reaction method with calcination and sintering temperature 925 o C and 950 o C respectively for 5 h, have been reported. Structural and electrical characteristics of the parent compound have significantly been tailored by the addition of the equal percentage of CaSnO3, CaSeO3 over a wide range of temperature (25 o C -400 o C) as well as frequency (1 kHz-1MHz). Analysis of room temperature X-ray diffraction (XRD) data confirmed the development of single-phase compound (with rhombohedral symmetry) with very small amount of impurity phase with higher concentrations (x). In the dielectric spectroscopy, two dielectric peaks are observed at around temperatures 210 o C and 320 o C indicating multiple phase transitions of different types including the ferroelectric to para-electric through anti-ferroelectric. Impedance analysis of data exhibits both negative/positive temperature coefficient of temperature (i.e., semiconductor behavior) of the materials. The Nyquist plots determine the grain and grain boundary effect in capacitive and resistive properties of the materials, and also the non-Debye type of relaxation. The room temperature hysteresis loop confirms the existence of ferroelectricity in the materials. The leakage current characteristics also determine the Ohmic behavior of the materials.