Studies of AC electrical conductivity and initial magnetic permeability of rare-earth-substituted Li–Co ferrites

Ata, Ali; Nimr, M.K. El; Attia, Smadar; Kony, D. El; Al-Hammadi, A. H.

doi:10.1016/j.jmmm.2005.01.085

Cited by 105 publications

(27 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All the samples are found to exhibit an increase in r with frequency and agree with the reported [80,81] trends in other ferrites. It is noticed that the conduction mechanism in ferrites is explained [82] on the basis of hopping of charge carriers, which are confined between the Fe 2?…”

supporting

confidence: 88%

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Lakshmi¹,

Sridhar

Govindraj

et al. 2016

J Mater Sci

View full text Add to dashboard Cite

Structural, morphological, magnetic, and dielectric investigations are carried out in Nb-doped (viz., for x equal to 0.0-0.4 by wt%) nanocrystalline Ni-Zn ferrites synthesized by hydrothermal method. XRD, IR studies infer the growth of nano structures and Fe 2 O 3 phase. Nb ions segregate at grain boundaries. Crystallite size (D) varies from 62 to 18 nm with x. FTIR absorption exhibits split at higher x. Saturation magnetization witnesses an overall decrease with x. Trends of M s (x) are explained by nature of dopant, preferential replacement, surface canting (Y-K angles) and lattice contraction. Variations of coercive field (H c ) and D infer singledomain to multi-domain morphological transformation. Occurrence of superparamagnetism (SPM) is predicted for zeroed values of H c and for a critical concentration x crit equal to 0.321. Enhanced Nb 5? -Fe 2? binding with dopant (x up to 0.2) results for decrease in dielectric constant e 0 r , loss factor tand and increase in resistivity q. Lowered ac conductivity is attributed to blockade of path by Nb 5? ions in the vicinity of B-sites. Relatively higher q (*10 8 X cm) and lower loss (tand *10 -2 -10 -3 ) evinced for 10 kHz. Enhanced core loss is realized with x manifested as lowered H c and tand to usher their utility in high-frequency applications.

show abstract

supporting

confidence: 88%

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Lakshmi¹,

Sridhar

Govindraj

et al. 2016

J Mater Sci

View full text Add to dashboard Cite

show abstract

“…The increase of electrical conductivity with increase in temperature and frequency may be related to increase of the drift mobility of the electron and hole by hopping conduction [14]. The total conductivity of the system is given by [15]: Here the first term on right hand side is dc conductivity due to band conduction which is independent of frequency. The second term is pure ac conductivity due to the hopping of charge carrier between the metal ions.…”

Section: Electrical Propertiesmentioning

confidence: 99%

Temperature and Frequency Dependence Electrical Properties of Zn_1-xCa_xO Nanoceramic

Das

Parashar

et al. 2016

Acta Phys. Pol. A

View full text Add to dashboard Cite

This work reports the temperature and frequency dependence electrical properties of Ca doped ZnO (Zn1−xCaxO, x = 0.01) nanoceramic synthesized by solid state reaction method. The X-ray spectra show that the synthesized powder has hexagonal wurtzite structure with space group P 63mc. The average crystallite size decreases with Ca doping. The increase in oxygen positional parameter (u) indicates lattice distortion in the crystal structure. Doping with Ca caused a slight shift in the (101) plane peak towards lower diffraction angle. The formation of pores in field emission scanning electron microscopy micrograph may be due to the defect created by Ca substitution. The electrical property was investigated by impedance spectroscopy in the temperature range 300-500• C. The synthesized sample shows temperature dependence relaxation phenomena and negative temperature coefficient of resistance effects. Electrical conductivity (σac) increases with increase in temperature as well as with frequency due to the drift mobility of electrons and hole by hopping conduction. Dielectric constant was found to decrease with increase in frequency and temperature. This decreases drastically in the magnitude of approximately < 10 times than the corresponding undoped one.

show abstract

“…The first term is dc conductivity due to the band conduction; it is a frequency independent term [31]. The second term is the pure ac conductivity, due to the hopping processes at the octahedral site.…”

Section: Ac Conductivitymentioning

confidence: 99%

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Dar

Batoo

Verma

et al. 2010

Journal of Alloys and Compounds

204

View full text Add to dashboard Cite

Studies of AC electrical conductivity and initial magnetic permeability of rare-earth-substituted Li–Co ferrites

Cited by 105 publications

References 27 publications

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Temperature and Frequency Dependence Electrical Properties of Zn_1-xCa_xO Nanoceramic

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Contact Info

Product

Resources

About

Studies of AC electrical conductivity and initial magnetic permeability of rare-earth-substituted Li–Co ferrites

Cited by 105 publications

References 27 publications

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Experimental characterization of nanocrystalline niobium-doped nickel–zinc ferrites: occurrence of superparamagnetism

Temperature and Frequency Dependence Electrical Properties of Zn1-xCaxO Nanoceramic

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Contact Info

Product

Resources

About

Temperature and Frequency Dependence Electrical Properties of Zn_1-xCa_xO Nanoceramic