On the magnetic compensation of magnesium doped Ni-Cr ferrites

Rais, A.; Addou, A.; Ameri, M.; Bouhadouza, N.; Merine, Asma

doi:10.1007/s00339-012-7304-9

Cited by 5 publications

(4 citation statements)

References 12 publications

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“…, where cations inside the round and square brackets occupy A-sites and B-sites, respectively, and  (degree of inversion) depends on thermal history and preparation condition. Its magnetic ordering temperature is of about 580C [7] that is far above the room temperature. It exhibits moderate saturation magnetization, excellent chemical, thermal and structural stability at room temperature [8].…”

Section: Introductionmentioning

confidence: 98%

Nickel–Yttrium Ferrite Nanopowders for Solving Environmental Problems

2019

Nanosist. Nanomater. Nanotehnol.

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Among the family of spinel ferrites, nickel ferrite NiFe 2 O 4 obtained by ceramic technology was widely studied due to its tremendous properties such as high electromagnetic performance, excellent chemical stability and mechanical hardness, and moderate saturation magnetization, making it as a good contender for the application as soft magnets and low-loss materials at high frequencies. The structure, mechanical, magnetic, electrical, and dielectric properties of nickel ferrite are dependent on several factors including the method of fabrication, sintering time and temperature, chemical composition, type and amount of dopant, grain structure. The sol-gel processing with autocombustion (SGA) technique was used for the synthesis of NiY x Fe 2x O 4 (x0.0, 0.1, 0.2, 0.3, 0.4, 0.5) ferrite nanoparticles. The mixed solution was dried at temperature around 403 K. During evaporation, the solution becomes viscous and finally formed as a xerogel. At further elevation of temperature, the organic constituents are decomposed with the generation of gases such as CO 2 , N 2 and H 2 O; therefore, the xerogel automatically ignited. The autocombustion was completed within a few seconds, yielding the nanopowders of nickel-yttrium ferrites. The XRD results confirm single-phase formation of the as-prepared NiFe 2 O 4 sample. The powders substituted with Y 3 ions, except the spinel-type phase, contain additional -Fe 2 O 3 and Y 2 O 3 phases too. The powder sizes decrease from 43 nm to 17 nm with increase in amount of Y 3 ions. The EDX results confirm the presence of Ni, Fe, Y, and O elements in Ni-Y-ferrite powders. The infrared (IR) spectra were recorded at the room temperature in the range from 400 cm 1 to 4000 cm 1 ; they confirm the spinel structure. As found, the adsorption capacity of Ni-Y ferrite increases, while the substitutions with Y 3+ ions increase. The adsorption process increases with increasing pH, has a maximum at pH7, and depends on the dye type.Серед феритів зі структурою шпінелі властивості фериту ніклю NiFe 2 O 4 , одержаного за керамічною технологією, є широко вивчені, оскільки він

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Section: Introductionmentioning

confidence: 98%

Nickel–Yttrium Ferrite Nanopowders for Solving Environmental Problems

2019

Nanosist. Nanomater. Nanotehnol.

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“…Dependences of and c on the substitution degreeFe 2 O 3 , and Cr 2 O 3 oxides at a temperature of 1623 K for 12 h. Furthermore, the authors of work[33] obtained c = 856 K for a specimen with the same composition, which was synthesized at a temperature of 1473 K also for 12 h, by using the precursors NiCO 3 , Fe 2 O 3 , and Cr 2 O 3 . At the same time, for the NiFe 2 O 4 ferrite obtained within the SGAC method, the Curie temperature is lower by 15 and 25 K, respectively (see Table…”

mentioning

confidence: 95%

Magnetic Hysteresis and Curie Temperature in Nickel-Chromium Ferrites Synthesized by Sol-Gel Auto-Combustion Method

Bushkova¹

2017

Ukr. J. Phys.

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Nanopowders of nickel-chromium ferrites with the general formula NiCr Fe2− O4 are synthesized, by using the sol-gel auto-combustion method. Specimens of all ferrite compositions had a cubic spinel structure. The average size of powder crystallites varied from 23 to 43 nm. After the powders were pressed and sintered at a temperature of 1573 K, the average size of crystallites grew to 65-83 nm. The shape of a hysteresis loop (the low coercivity c) showed that the specimens were soft magnetic materials. The residual magnetic field induction r decreased with the growing concentration of Cr 3+ ions due to the weakening of the interaction between the spinel sublattices, whereas c increased at that. The increase of the Cr 3+ ion content in the ferrite specimens diminished the value of specific saturation magnetization s from 33.9 to 7.7 A m 2 / , which testifies that less magnetic Cr 3+ ions substitute Fe 3+ ones in the ferrite octahedral sublattice. The magnetic moments calculated for the proposed cation distribution in the framework of the Néel two-sublattice model turned out some lower than the experimentally measured values, which can be explained as a manifestation of the tilted spin effect and the influence of a surface layer 0.22-2.01 nm in thickness with a violated magnetic structure. As the temperature was lowered to 77 K, the magnetic parameters of the ferrite cores increased owing to their superparamagnetic properties. The Curie temperature decreased from 831 to 685 K with the growth of Cr content.

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“…For this purpose, the study on the influence of chromium substitution on the physical properties of spinel ferrites is of interest. The effects of substitution of Fe 3+ by Cr 3+ in NiFe 2−x Cr x O 4 were studied by various workers [4]- [8]. It was shown that Cr 3+ prefers to locate at the octahedral sites and with a successive increase of Cr 3+ , a small amount of Ni 2+ or Cr 3+ can reside in the tetrahedral sites [4]- [6].…”

Section: Introductionmentioning

confidence: 99%

“…The replacement of Fe 3+ (5 μ B ) with Cr 3+ (3 μ B ) at the B-site in the materials causes reductions in the magnetization of the octahedral sublattice and the intersublattice exchange interaction and consequently the Curie temperature [4], [7], [9]. The chromium-doped spinel ferrites also exhibit the effect of magnetic compensation [8], [10]- [12] at temperature where the spontaneous magnetizations of the two sublattices of the ferrite structure become equal. Belov [12] was the first to observe this phenomenon in NiFe 2−x Cr x O 4 with x = 0.9 and 1.…”

Section: Introductionmentioning

confidence: 99%

Synchrotron and Magnetic Study of Chromium-Substituted Nickel Ferrites Prepared by Using Sol-Gel Route

et al. 2014

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Structural and magnetic properties of NiCr x Fe 2−x O 4 (x = 0.7 and 0.9) spinel ferrites prepared by sol-gel route have been investigated using synchrotron X-ray powder diffraction (SXPD) and magnetization measurements. The gel products after annealing at 1000°C for 2 h are found to crystallize in cubic phase. Rietveld refinements of X-ray diffraction and SXPD patterns revealed that the compounds are almost perfect inverse spinel with only few percents of nickel atoms located at the tetrahedral sites. Transmission electron microscopy (TEM) images showed that the samples are composed of nanoparticles with mean diameter in agreement with crystallite size determined by the Rietveld analysis. The spontaneous magnetization M s as a function of temperature was determined via magnetization curves measured using vibrating sample magnetometer in a temperature range from 88 K to above Curie temperature in applied fields up to 10 kOe. The sample x = 0.9 shows a cancelation of sublattice magnetizations at 400 K. The temperature dependence of saturation magnetization M s of the samples can be described in terms of molecular-field model for collinear spins with the derived cation distributions.

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On the magnetic compensation of magnesium doped Ni-Cr ferrites

Cited by 5 publications

References 12 publications

Nickel–Yttrium Ferrite Nanopowders for Solving Environmental Problems

Nickel–Yttrium Ferrite Nanopowders for Solving Environmental Problems

Magnetic Hysteresis and Curie Temperature in Nickel-Chromium Ferrites Synthesized by Sol-Gel Auto-Combustion Method

Synchrotron and Magnetic Study of Chromium-Substituted Nickel Ferrites Prepared by Using Sol-Gel Route

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