ABSTRACT Effect of Pr–Ni substitution on structural and magnetic properties of Ca0.5Ba0.5−xPrxNiy... more ABSTRACT Effect of Pr–Ni substitution on structural and magnetic properties of Ca0.5Ba0.5−xPrxNiyFe12−yO19 (x=0.00–0.10 and y=0.00–1.00) prepared by the sol–gel auto combustion method were investigated. The XRD analysis confirmed the single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as Pr–Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to be completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr–Ni substitution. The coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the samples fall in the range of M-type hexa-ferrites.
Room temperature resistivity measurements were carried out for Cu Cd Fe O ferrite samples for 0.0... more Room temperature resistivity measurements were carried out for Cu Cd Fe O ferrite samples for 0.0 F x F 1.0 1yx x 2 4 prepared by ceramic method. At lower Cd concentration, the increase in DC resistivity is attributed to the hindering of the hopping mechanism between Fe 2q and Fe 3q. This may be due to the stable bond formation of Cu 3q q Fe 2q at octahedral sites. The decrease in resistivity at higher Cd content is attributed to the lower concentration of the stable bond of Cu 3q q Fe 2q. Two distinct regions have been noted for temperature dependent resistivity, namely paramagnetic and ferrimagnetic regions. Activation energy in paramagnetic region is greater than in the ferrimagnetic region which shows Ž. hopping conduction at higher temperatures. Seebeck coefficient a was measured for all the samples which shows that all the CuCd ferrite samples are degenerate-type semiconductors.
A series of Y-type hexa-ferrites with composition, Ba 2 Zn 2 Tb x Fe 12Àx O 22 (0 6 x 6 0.1), wer... more A series of Y-type hexa-ferrites with composition, Ba 2 Zn 2 Tb x Fe 12Àx O 22 (0 6 x 6 0.1), were synthesized by the sol-gel auto-combustion technique. The X-ray powder diffraction technique was employed to confirm the formation of Y-type phase. The dispersion in dielectric constant, dielectric loss, and r ac with frequency shows that the dispersion at low frequencies is due to Maxwell-Wagner type of interfacial polarization in general and the hopping of charge carrier between Fe 2+ and Fe 3+ ions. The substitution of Tb +3 inhibit the valence exchange of Fe +2 and Fe 3+ and therefore the dielectric permittivity decreased. The DC resistivity increased from 7.29 Â 10 7 to 4.73 Â 10 8 X cm with increasing Tb-contents due to the unavailability of Fe 3+ ions at octahedral sites. The enhanced resistivity of Y-type hexa ferrites makes them suitable candidates for multi-layer chip inductor applications.
ABSTRACT The impacts of terbium (Tb) contents on magnetic, ferromagnetic resonance (FMR), electri... more ABSTRACT The impacts of terbium (Tb) contents on magnetic, ferromagnetic resonance (FMR), electrical and dielectric properties of Ni 1 À x Tb x Fe 2 O 4 ferrites were investigated. A vibrating sample magnetometer was employed to probe the magnetic properties of the samples at room temperature. It was found that with the increased terbium content, the coercive force and saturation magnetization were decreased which may be attributed to spin canting. Magnetic dynamics of the samples were studied by ferromagnetic resonance in X band (9.5 GHz) at room temperature. The incorporation of terbium sufficiently lowers the FMR line-width. The decrease in FMR line-width is attributed to the reduction of super-exchange interactions. The DC electrical resistivity and activation energy are higher for the substituted samples. The dielectric constant, dielectric loss (tan δ) and AC-conductivity decreased on account of doping. The decrease in dielectric constant is imputed to the reduction in the internal viscosity of the doped samples. The dielectric data are explained on the basis of space charge polarization. As Ni–Tb ferrites have low value of coercivity, high dielectric constant and low tan δ, they may be attractive for application in switching and memory storage devices.
Effect of Pr–Ni substitution on structural and magnetic properties of Ca 0.5Ba 0.5 x Prx Ni y F... more Effect of Pr–Ni substitution on structural and magnetic properties of Ca 0.5Ba 0.5 x Prx Ni y Fe12 y O19 ( x ¼ 0.00– 0.10 and y ¼ 0.00 –1.00) prepared y the sol –gel auto combustion method were investigated. The XRD analysis confi rmed the single phase M-type hexa-ferrite structure. The lattice arameters were found to increase as Pr –Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to e completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr –Ni substitution. he coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the mples fall in the range of M-type hexa-ferrites.
ABSTRACT Effect of Pr–Ni substitution on structural and magnetic properties of Ca0.5Ba0.5−xPrxNiy... more ABSTRACT Effect of Pr–Ni substitution on structural and magnetic properties of Ca0.5Ba0.5−xPrxNiyFe12−yO19 (x=0.00–0.10 and y=0.00–1.00) prepared by the sol–gel auto combustion method were investigated. The XRD analysis confirmed the single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as Pr–Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to be completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr–Ni substitution. The coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the samples fall in the range of M-type hexa-ferrites.
Room temperature resistivity measurements were carried out for Cu Cd Fe O ferrite samples for 0.0... more Room temperature resistivity measurements were carried out for Cu Cd Fe O ferrite samples for 0.0 F x F 1.0 1yx x 2 4 prepared by ceramic method. At lower Cd concentration, the increase in DC resistivity is attributed to the hindering of the hopping mechanism between Fe 2q and Fe 3q. This may be due to the stable bond formation of Cu 3q q Fe 2q at octahedral sites. The decrease in resistivity at higher Cd content is attributed to the lower concentration of the stable bond of Cu 3q q Fe 2q. Two distinct regions have been noted for temperature dependent resistivity, namely paramagnetic and ferrimagnetic regions. Activation energy in paramagnetic region is greater than in the ferrimagnetic region which shows Ž. hopping conduction at higher temperatures. Seebeck coefficient a was measured for all the samples which shows that all the CuCd ferrite samples are degenerate-type semiconductors.
A series of Y-type hexa-ferrites with composition, Ba 2 Zn 2 Tb x Fe 12Àx O 22 (0 6 x 6 0.1), wer... more A series of Y-type hexa-ferrites with composition, Ba 2 Zn 2 Tb x Fe 12Àx O 22 (0 6 x 6 0.1), were synthesized by the sol-gel auto-combustion technique. The X-ray powder diffraction technique was employed to confirm the formation of Y-type phase. The dispersion in dielectric constant, dielectric loss, and r ac with frequency shows that the dispersion at low frequencies is due to Maxwell-Wagner type of interfacial polarization in general and the hopping of charge carrier between Fe 2+ and Fe 3+ ions. The substitution of Tb +3 inhibit the valence exchange of Fe +2 and Fe 3+ and therefore the dielectric permittivity decreased. The DC resistivity increased from 7.29 Â 10 7 to 4.73 Â 10 8 X cm with increasing Tb-contents due to the unavailability of Fe 3+ ions at octahedral sites. The enhanced resistivity of Y-type hexa ferrites makes them suitable candidates for multi-layer chip inductor applications.
ABSTRACT The impacts of terbium (Tb) contents on magnetic, ferromagnetic resonance (FMR), electri... more ABSTRACT The impacts of terbium (Tb) contents on magnetic, ferromagnetic resonance (FMR), electrical and dielectric properties of Ni 1 À x Tb x Fe 2 O 4 ferrites were investigated. A vibrating sample magnetometer was employed to probe the magnetic properties of the samples at room temperature. It was found that with the increased terbium content, the coercive force and saturation magnetization were decreased which may be attributed to spin canting. Magnetic dynamics of the samples were studied by ferromagnetic resonance in X band (9.5 GHz) at room temperature. The incorporation of terbium sufficiently lowers the FMR line-width. The decrease in FMR line-width is attributed to the reduction of super-exchange interactions. The DC electrical resistivity and activation energy are higher for the substituted samples. The dielectric constant, dielectric loss (tan δ) and AC-conductivity decreased on account of doping. The decrease in dielectric constant is imputed to the reduction in the internal viscosity of the doped samples. The dielectric data are explained on the basis of space charge polarization. As Ni–Tb ferrites have low value of coercivity, high dielectric constant and low tan δ, they may be attractive for application in switching and memory storage devices.
Effect of Pr–Ni substitution on structural and magnetic properties of Ca 0.5Ba 0.5 x Prx Ni y F... more Effect of Pr–Ni substitution on structural and magnetic properties of Ca 0.5Ba 0.5 x Prx Ni y Fe12 y O19 ( x ¼ 0.00– 0.10 and y ¼ 0.00 –1.00) prepared y the sol –gel auto combustion method were investigated. The XRD analysis confi rmed the single phase M-type hexa-ferrite structure. The lattice arameters were found to increase as Pr –Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to e completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr –Ni substitution. he coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the mples fall in the range of M-type hexa-ferrites.
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Papers by Misbah Islam
y the sol –gel auto combustion method were investigated. The XRD analysis confi rmed the single phase M-type hexa-ferrite structure. The lattice
arameters were found to increase as Pr –Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to
e completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr –Ni substitution.
he coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the
mples fall in the range of M-type hexa-ferrites.
y the sol –gel auto combustion method were investigated. The XRD analysis confi rmed the single phase M-type hexa-ferrite structure. The lattice
arameters were found to increase as Pr –Ni content increases, which is attributed to the ionic size of the implicated cations. The Pr–Ni seems to
e completely soluble in the lattice. Transmission electron microscopy reveals that the grain size decreases with increase of Pr –Ni substitution.
he coercivity and remanent magnetization ranges from 1511 to 1925 (Oe) and 21.4 to 26.5 (emu/g), respectively. The coercivity values of all the
mples fall in the range of M-type hexa-ferrites.