Effect of Copper Oxide Content on Intrinsic Properties of MgCuZn Ferrite

Rezlescu, E.; Rezlescu, N.; Popa, P.D.; Rezlescu, L.; Pasnicu, C.; Craus, M.L.

doi:10.1016/s0025-5408(98)00050-6

Cited by 44 publications

(23 citation statements)

References 10 publications

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“…low temperature (ferromagnetic) region I and high temperature (paramagnetic) region II. Similar slope change near Curie transition temperature in Arrhenius plots for DC conductivity was observed by Rezlescu et al [9,21] and it was attributed to the influence of ferromagnetic ordering on conduction mechanism. In principle, this is due to destruction of spontaneous magnetization and the change in additional charge carrier concentration in the neighborhood of Curie transition temperature.…”

Section: Resultssupporting

confidence: 84%

“…Rezlescu et al [9] reported an increase of DC electrical conductivity with temperature by about three orders of magnitude only in Ta 2 O 5 and PbO added MgCuZn ferrites. In another work, Rezlescu et al [21] reported an increase in DC conductivity with temperature for MgCuZn ferrites of about four orders of magnitude. This strong increase in conductivity with temperature was attributed mainly to the thermally activated mobility of the charge carriers, but not to thermally activated creation of these carriers.…”

Section: Resultsmentioning

confidence: 92%

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DC conductivity and Seebeck coefficient of nonstoichiometric MgCuZn ferrites

Madhuri

Kiran

Reddy

et al. 2017

Materials Science-Poland

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Nonstoichiometric series of Mg 0.5 − x Cu x Zn 0.5 Fe 1.9 O 4 − δ where x = 0.0, 0.1, 0.15, 0.2 and 0.25 has been synthesized by conventional solid state reaction route. The single phase spinel structure of the double sintered ferrites was confirmed by X-ray diffraction patterns (XRD). The ferrite series was studied in terms of DC electrical conductivity and thermoelectric power in the temperature ranging from room temperature to 300°C and 400°C, respectively. It was observed that DC electrical conductivity and Seebeck coefficient α decreased with the increase in x. DC electrical conductivity was found to decrease by about 4 orders. All the compositions showed a negative Seebeck coefficient exhibiting n-type semiconducting nature. From the above experimental results, activation energy and mobility of all the samples were estimated. Small polaron hopping conduction mechanism was suggested for the series of ferrites. Owing to their low conductivity the nonstoichiometric MgCuZn ferrites are the best materials for transformer core and high definition television deflection yokes.

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Section: Resultssupporting

confidence: 84%

Section: Resultsmentioning

confidence: 92%

DC conductivity and Seebeck coefficient of nonstoichiometric MgCuZn ferrites

Madhuri

Kiran

Reddy

et al. 2017

Materials Science-Poland

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“…(1) By a quick combustion, hydroxides convert to oxides and ferrite synthesis begins by the reaction LiOH + 5Fe (OH) 3 …”

Section: Preparation and Study Of Lithium Based Ferritementioning

confidence: 99%

“…The beneficial effect of copper ions on the densification of LiZn ferrite can be reasonably explained through a high atomic mobility of Cu ions at relatively low temperature. The copper ions may facilitate the lattice diffusion of the cations and promote densification [3]. Due to low treatment temperature (1000 °C), the samples remained porous, even after a prolonged treatment (80 minutes).…”

Section: Preparation and Study Of Lithium Based Ferritementioning

confidence: 99%

Li and Ba ferrite nanoparticles prepared by self combustion

Rezlescu

Doroftei

et al. 2004

phys. stat. sol. (c)

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The microstructure evolution during the heat treatments of Ba and Li ferrite powders prepared by self combustion is reported in terms of the effect of treatment time on densification, grain growth and some magnetic properties. The optimum size of the Ba ferrite crystallites was obtained by thermal annealing at 1000 °C for 10 min. The coercivity H c increases with increasing the annealing time and attains a maximum value of 4900 Oe which is much larger than that obtained by using a conventional method for the preparation of Ba hexaferrite. Li ferrite prepared by self combustion is characterized by low density and high electrical resistivity. O having a 10% metal concentration were prepared. Separately, an aqueous solution with 10 % polyvinyl alcohol concentration was prepared. Then, equal parts of the two solutions were mixed and a homogeneous solution with 5% metals and 5% colloid was obtained. Then, a small amount of ammonium hydroxide was added to the solution to adjust the pH value (pH ~ 8). The precipitation of metal hydroxides into the colloidal medium takes place according to the reaction LiNO 3 + 5Fe (NO 3 ) 3 + 16NH 4 OH → LiOH + 5Fe (OH) 3 + 16NH 4 (NO 3 ).(1) By a quick combustion, hydroxides convert to oxides and ferrite synthesis begins by the reaction LiOH + 5Fe (OH) 3 → LiFe 5 O 8 + 8H 2 O .(2) The ferrite powder is composed of submicron particles and small values of magnetic parameters. The resulting powders after combustion were heated at 500 °C for 30 minutes and then pressed in a disc and toroid shape in a stainless steel die under a pressure of about 3 · 10 7 N/m 2 . The pellets (17 mm diameter, 2-3 mm thick) and toroids (18 mm exterior diameter, 13 mm interior diameter, 3-4 mm thick) were heat treated in air at 1000 °C for 10, 20, 40 and 80 minutes to realize densification. The sintered ceramics were analyzed using X-ray diffraction to evidence the structure. After each thermal treatment the volume shrinkage, saturation magnetization, remanence magnetization and electrical resistivity were measured. The green pressed samples exhibit high porosity. By sintering at 1000 °C a strong volume shrinkage of specimens was noticed, which depends on the sintering time. From Fig. 1 one can observe that the volume significantly decreases after 20 minutes of the thermal treatment. By increasing the treatment time,

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“…It was reported that electromagnetic properties of the multilayer chip ferrite components [9,18,[20][21][22] are influenced by the internal stresses and the diffusion of Ag buried in ferrite [23][24][25][26][27][28][29][30]. As the magnetostriction of MgCuZn ferrites is lower than that of NiCuZn ferrites, it was expected that the multilayer chip inductor using MgCuZn ferrite [31] would show higher magnetic properties than that using NiCuZn ferrite.…”

Section: Introductionmentioning

confidence: 99%