Localized canted spin behaviour in

Thummer, K. P.; Chhantbar, M. C.; Modi, K. B.; Baldha, G.J.; Joshi, H. H.

doi:10.1016/j.jmmm.2004.02.017

Cited by 62 publications

(18 citation statements)

References 17 publications

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“…As it can be seen, magnetization increases firstly and got a maximum, and then decreases. These variations in bulk samples verify the spin canting and the existence of Yaffit-Kittle angles in the samples with x ≤ 0.4 [23].…”

Section: Resultssupporting

confidence: 68%

Enhanced Magnetization in Mg–Zn Ferrite Nanoparticles, Prepared by Mechanochemical Processing

Mozaffari

Zare

2015

J Supercond Nov Magn

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One-step mechanochemical processing is one of the most useful and effective methods to produce nanoparticles. Prepared materials by this method show novel properties. In this work, Mg-substituted Zn ferrite (Mg x Zn 1−x Fe 2 O 4 ; x = 0.0, 0.2, 0.4, 0.6) nanoparticles were prepared by one-step mechanochemical processing for the first time. In addition, bulk samples with the same compositions were prepared by conventional ceramic method, which served as reference samples. The samples were characterized by the X-ray diffraction and field emission electron microscopy. By a comparison between I (220)/I (222) intensity ratios in X-ray diffraction patterns of the samples prepared by one-step mechanochemical processing and those of the bulk samples, changes in the cation distribution of the samples prepared by one-step mechanochemical processing were followed. Lattice parameters and magnetic properties of the all samples were measured, and their behaviors were discussed.

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Section: Resultssupporting

confidence: 68%

Enhanced Magnetization in Mg–Zn Ferrite Nanoparticles, Prepared by Mechanochemical Processing

Mozaffari

Zare

2015

J Supercond Nov Magn

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“…Studies of different mixed spinel ferrites [3,4,9,10] have shown that the ferrite is a semiconductor in which conduction is carried out through the hopping of the charge carriers between Fe 2+ -Fe 3+ and the other transition elements, which have different valences. In the present composition under investigation Cu 2+ ions in the unit cell are occupying the octahedral B-sites as reported earlier [17,18] and Mg 2+ ions are almost exclusively in the octahedral B-sites [19,20], while Ga 3+ ions occupy both B-and A-sites [21].…”

Section: Methodsmentioning

confidence: 99%

“…), is a ferromagnetic system. The type of cations and their distribution between the two interstitial sites in these ferrites determine many of the electrical and magnetic properties of the ferrites [3,4]. Magnesium ferrite, MgFe 2 O 4 , is a partially inverse spinel [5,6] and can be considered as a collinear ferromagnet whose degree of inversion is sensitive to the sample preparation [7], whereas CuFe 2 O 4 ferrite exhibits switching and changing semiconducting properties [8].…”

Section: Introductionmentioning

confidence: 99%

“…Magnesium ferrite, MgFe 2 O 4 , is a partially inverse spinel [5,6] and can be considered as a collinear ferromagnet whose degree of inversion is sensitive to the sample preparation [7], whereas CuFe 2 O 4 ferrite exhibits switching and changing semiconducting properties [8]. Various investigations of the mixed ferrites Mg-Mn [4], Mg-Ca [3], Co-Cu [9] and Mn-Cu [10] provided a cation distribution, electrical and magnetic properties of some interest.…”

Section: Introductionmentioning

confidence: 99%

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Low frequency conductivity study of gallium‐substituted magnesium–copper spinel ferrite

Kaiser

Ata‐Allah

2005

Physica Status Solidi (b)

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Mixed ferrites with the chemical formula Mg 0.5 Cu 0.5 Ga x Fe 2-x O 4 (0.0 ≤ x ≤ 0.5) were prepared by a ceramic route. X-ray diffraction results confirmed the presence of single-phase spinel structure for these samples. Electrical properties of these ferrites at various compositions were investigated from room temperature up to 550 K in the frequency range 10 2 -10 5 Hz. The obtained results revealed semiconductor behavior at high frequency and metallic behavior at low frequency in these materials. All studied compositions exhibit a transition with a change in the slope of the conductivity versus temperature curve. The obtained transition temperature T C is found to decrease linearly with increasing Ga concentration. As Ga substitutes Fe in these compounds the activation energy for electrical conduction in the ferrimagnetic region (E f ) has a small variation with frequency. In contrast, the activation energy in the paramagnetic region (E p ) shows undefined behavior reflecting the nature of this disordered state. The relation of the universal exponent s with temperature gives evidence for the presence of the large overlap polaron (LOP) hopping conduction mechanism in these compounds. The obtained results are explained in the light of the cation -anioncation and cation -cation interactions present over the octahedral B-sites in the spinel structure.

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“…ions only in the as-prepared sample. However, the smaller value of A-site isomer shift compared with B-site is due to a large covalency at the A-site [28,29]. Moreover, the lower value of the octahedral hyperfine field compared with the tetrahedral one may be considered on the basis of superexchange interactions [30].…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

Cation distribution and enhanced surface effects on the temperature-dependent magnetization of as-prepared NiFe2O4 nanoparticles

Nadeem

Siddique

2015

Appl. Phys. A

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Nickel ferrite, i.e., NiFe 2 O 4 , nanoparticles are synthesized by sol-gel method using urea as a neutralizing agent. The formation of spinel phase and crystal structure of the as-prepared sample is analyzed by X-ray diffraction and transmission electron microscope. In order to confirm phase formation and cation arrangement, room temperature 57 Fe Mössbauer spectroscopy is employed. The degree of inversion (i) estimated from the relative peak area is found to be 0.6, which confirms a mixed spinel structure of the asprepared sample. Zero-field-cooled/field-cooled measurements showed evidence of superparamagnetic behavior associated with the nanosized particles. Hysteresis loop measurements revealed temperature-dependent magnetic properties: The coercive field (H C ) decreases with increasing temperature and deviates from the Kneller's law for ferromagnetic nanostructures; and the saturation magnetization (M s ) follows modified Bloch's law in the temperature range between 25 and 400 K. However, below 25 K, an abrupt increase in magnetization of nanoparticles is observed. In order to understand this behavior, an additional contribution has to be added to the core magnetization to properly fit the data. Hence, a surface correction term to the Bloch's law is found to describe the temperature dependence of magnetization in the core-shell NiFe 2 O 4 nanoparticles.

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Localized canted spin behaviour in

Cited by 62 publications

References 17 publications

Enhanced Magnetization in Mg–Zn Ferrite Nanoparticles, Prepared by Mechanochemical Processing

Enhanced Magnetization in Mg–Zn Ferrite Nanoparticles, Prepared by Mechanochemical Processing

Low frequency conductivity study of gallium‐substituted magnesium–copper spinel ferrite

Cation distribution and enhanced surface effects on the temperature-dependent magnetization of as-prepared NiFe2O4 nanoparticles

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