ABSTRACT We carried out a systematic study on the effect of the substitution of Ti2+ and Ru4+ ion... more ABSTRACT We carried out a systematic study on the effect of the substitution of Ti2+ and Ru4+ ions for Fe3+ ions on the structural and magnetic properties of the strontium ferrite SrFe12-2xRuxTixO19 nanoparticles with (0 ≤ x ≤ 0.3), using x-ray diffraction, Quantum Design PPMS-9 magnetometry, and electrical resistivity. A clear irreversibility between the zero-field-cooled and field-cooled curves was observed below room temperature and the zero-field-cooled magnetization curves displayed a broad peak at a temperature TM. These results were discussed within the framework of random particle assembly model and associated with the magnetic domain wall motion. The resistivity data showed some kind of a transition from insulator to perfect insulator around TM. The high-temperature magnetization measurements exhibited sharp peaks just below Tc indicating a superparamagnetic behavior. With Ru-Ti substitution, the saturation magnetization at 5 K showed small variations were it slightly increased with increasing x up to 0.2, and then decrease for x = 0.3, while the coercivity decreased monotonically, recording a reduction of about 78% at x = 0.3. These results were discussed in light of the cationic distributions based on the results of the structural refinements.
fullprof refinement, full structural information based on Rietveld refinement of XRD pattern cont... more fullprof refinement, full structural information based on Rietveld refinement of XRD pattern contains M-type barium hexaferrite (BaFe12O19) as a main phase, and Hematite (a-Fe2O3) as a secondary phase. to download, right click on the dataset picture and save link as..
The main essence of this study is about the structural analysis of barium hexaferrite material, b... more The main essence of this study is about the structural analysis of barium hexaferrite material, based on XRD pattern fitting using Rietveld refinement. Our methodology start by preparing a samples of barium iron oxide materials, with different stoichiometric ratios, under different laboratory conditions. In an attempt to understand the formation of barium hexaferrite phases, in order to synthesis a pure phase of M-type barium hexaferrite (BaFe12O19). As well as to understand the effect of temperature and impurities on the resulted phases. In the beginning, a precursor material was prepared in order to obtain M-type barium hexaferrite (BaFe12O19) samples, and modifying the proportion of Fe:Ba ratio in each sample ascending from (11.5) to (16:16), for five samples and synthesizing them under the same laboratory conditions. The analysis of these samples shows that the M-type barium hexa ferrite was not affected structurally or quantitatively, and the increase of the iron oxide quantity...
Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequ... more Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequent sintering at different temperatures (1100, 1200, and 1300° C). The samples sintered at 1100° C exhibited good hard magnetic properties, although a decrease in saturation magnetization from 70.2 emu/g for the unsubstituted sample down to 57 emu/g for the sample with x = 0.3 was observed. The drop in saturation magnetization results mainly from the presence of secondary nonmagnetic oxides. The samples sintered at temperatures >1200° C showed an improvement in saturation magnetization, and a sharp drop in coercivity. This behavior was associated with the development of the W-type hexaferrite, the particle growth, and possibly the spin reorientation transition from easy-axis to easy-plane. compositions of various ferrites were controlled to obtain materials with desirable properties for a wide range of applications 1-3 .
In this article we report on the structural and magnetic properties of BaFe 12-4x Mo x Zn 3x O 19... more In this article we report on the structural and magnetic properties of BaFe 12-4x Mo x Zn 3x O 19 hexaferrites with Mo-Zn substitution for Fe ions. The starting materials were commensurate with the BaM stoichiometry, and the Mo:Zn ratio was 1:3. The powder precursors were prepared by high energy ball milling, and subsequently sintered at temperatures from 1100 to 1300° C. The structural analyses indicated that all samples sintered at 1100° C were dominated by a major M-type hexaferrite phase. The relative abundance of the BaMoO 4 and Zn-spinel secondary phases increased with increasing the concentration of the substituents, resulting in a decrease of the saturation magnetization from about 67 emu/g (for x = 0.0) to 55 emu/g (for x = 0.3). The coercivity also decreased from 3275 Oe (for x = 0.0) to 900 Oe (for x = 0.3), demonstrating the ability to tune the coercivity to the range useful for magnetic recording by the substitution process. The saturation magnetization improved significantly with sintering at T > 1100° C, and the coercivity decreased significantly, signaling the transformation of the samples to soft magnetic materials. These magnetic changes were due to the high-temperature reaction of the spinel phase with the BaM phase to produce the W-type hexaferrite phase on the one hand, and to the growth of the particles on the other hand. The magnetic phases were further investigated using Mössbauer spectroscopy and thermomagnetic measurements. Our study indicated that the sample with x = 0.2 has the highest saturation magnetization (74 emu/g at sintering temperature of 1300° C) and a tunable coercivity between 2100 Oe and 450 Oe.
ABSTRACT We carried out a systematic study on the effect of the substitution of Ti2+ and Ru4+ ion... more ABSTRACT We carried out a systematic study on the effect of the substitution of Ti2+ and Ru4+ ions for Fe3+ ions on the structural and magnetic properties of the strontium ferrite SrFe12-2xRuxTixO19 nanoparticles with (0 ≤ x ≤ 0.3), using x-ray diffraction, Quantum Design PPMS-9 magnetometry, and electrical resistivity. A clear irreversibility between the zero-field-cooled and field-cooled curves was observed below room temperature and the zero-field-cooled magnetization curves displayed a broad peak at a temperature TM. These results were discussed within the framework of random particle assembly model and associated with the magnetic domain wall motion. The resistivity data showed some kind of a transition from insulator to perfect insulator around TM. The high-temperature magnetization measurements exhibited sharp peaks just below Tc indicating a superparamagnetic behavior. With Ru-Ti substitution, the saturation magnetization at 5 K showed small variations were it slightly increased with increasing x up to 0.2, and then decrease for x = 0.3, while the coercivity decreased monotonically, recording a reduction of about 78% at x = 0.3. These results were discussed in light of the cationic distributions based on the results of the structural refinements.
fullprof refinement, full structural information based on Rietveld refinement of XRD pattern cont... more fullprof refinement, full structural information based on Rietveld refinement of XRD pattern contains M-type barium hexaferrite (BaFe12O19) as a main phase, and Hematite (a-Fe2O3) as a secondary phase. to download, right click on the dataset picture and save link as..
The main essence of this study is about the structural analysis of barium hexaferrite material, b... more The main essence of this study is about the structural analysis of barium hexaferrite material, based on XRD pattern fitting using Rietveld refinement. Our methodology start by preparing a samples of barium iron oxide materials, with different stoichiometric ratios, under different laboratory conditions. In an attempt to understand the formation of barium hexaferrite phases, in order to synthesis a pure phase of M-type barium hexaferrite (BaFe12O19). As well as to understand the effect of temperature and impurities on the resulted phases. In the beginning, a precursor material was prepared in order to obtain M-type barium hexaferrite (BaFe12O19) samples, and modifying the proportion of Fe:Ba ratio in each sample ascending from (11.5) to (16:16), for five samples and synthesizing them under the same laboratory conditions. The analysis of these samples shows that the M-type barium hexa ferrite was not affected structurally or quantitatively, and the increase of the iron oxide quantity...
Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequ... more Molybdenum-zinc substituted hexaferrites were synthesized by high-energy ball milling and subsequent sintering at different temperatures (1100, 1200, and 1300° C). The samples sintered at 1100° C exhibited good hard magnetic properties, although a decrease in saturation magnetization from 70.2 emu/g for the unsubstituted sample down to 57 emu/g for the sample with x = 0.3 was observed. The drop in saturation magnetization results mainly from the presence of secondary nonmagnetic oxides. The samples sintered at temperatures >1200° C showed an improvement in saturation magnetization, and a sharp drop in coercivity. This behavior was associated with the development of the W-type hexaferrite, the particle growth, and possibly the spin reorientation transition from easy-axis to easy-plane. compositions of various ferrites were controlled to obtain materials with desirable properties for a wide range of applications 1-3 .
In this article we report on the structural and magnetic properties of BaFe 12-4x Mo x Zn 3x O 19... more In this article we report on the structural and magnetic properties of BaFe 12-4x Mo x Zn 3x O 19 hexaferrites with Mo-Zn substitution for Fe ions. The starting materials were commensurate with the BaM stoichiometry, and the Mo:Zn ratio was 1:3. The powder precursors were prepared by high energy ball milling, and subsequently sintered at temperatures from 1100 to 1300° C. The structural analyses indicated that all samples sintered at 1100° C were dominated by a major M-type hexaferrite phase. The relative abundance of the BaMoO 4 and Zn-spinel secondary phases increased with increasing the concentration of the substituents, resulting in a decrease of the saturation magnetization from about 67 emu/g (for x = 0.0) to 55 emu/g (for x = 0.3). The coercivity also decreased from 3275 Oe (for x = 0.0) to 900 Oe (for x = 0.3), demonstrating the ability to tune the coercivity to the range useful for magnetic recording by the substitution process. The saturation magnetization improved significantly with sintering at T > 1100° C, and the coercivity decreased significantly, signaling the transformation of the samples to soft magnetic materials. These magnetic changes were due to the high-temperature reaction of the spinel phase with the BaM phase to produce the W-type hexaferrite phase on the one hand, and to the growth of the particles on the other hand. The magnetic phases were further investigated using Mössbauer spectroscopy and thermomagnetic measurements. Our study indicated that the sample with x = 0.2 has the highest saturation magnetization (74 emu/g at sintering temperature of 1300° C) and a tunable coercivity between 2100 Oe and 450 Oe.
Uploads
Papers by Yazan Maswadeh