Site Preference for Fe in Zn-Doped Y-Type Barium Hexaferrite

Kim, Chin Mo; Rhee, Chan Hyuk; Kim, Chul Sung

doi:10.1109/tmag.2012.2198877

Cited by 10 publications

(2 citation statements)

References 13 publications

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“…The lattice constant a and c are 5.8613(1) Å and 43.503(1) Å, respectively. These results for unit cell parameters are in good agreement with the values published earlier for the Ba 2 Mg 2 Fe 12 O 22 and Ba 2 Co 2 Fe 12 O 22 hexaferrites [17,19,32,33,34]. As expected, despite the significant degree of substitution, no drastic changes were observed in the unit cell parameters of Ba 2 Mg 0.4 Co 1.6 Fe 12 O 22 due to the similar ionic radii of Co 2+ (0.58 Å) and Mg 2+ (0.57 Å) [31] cations.…”

Section: Resultssupporting

confidence: 92%

Study of the Structural and Magnetic Properties of Co-Substituted Ba2Mg2Fe12O22 Hexaferrites Synthesized by Sonochemical Co-Precipitation

et al. 2019

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Ba2Mg0.4Co1.6Fe12O22 was prepared in powder form by sonochemical co-precipitation and examined by X-ray diffraction, Mössbauer spectroscopy and magnetization measurements. Careful XRD data analyses revealed the Y-type hexaferrite structure as an almost pure phase with a very small amount of CoFe2O4 as an impurity phase (about 1.4%). No substantial changes were observed in the unit cell parameters of Ba2Mg0.4Co1.6Fe12O22 in comparison with the unsubstituted compound. The Mössbauer parameters for Ba2Mg0.4Co1.6Fe12O22 were close to those previously found (within the limits of uncertainty) for undoped Ba2Mg2Fe12O22. Isomer shifts (0.27–0.38 mm/s) typical for high-spin Fe3+ in various environments were evaluated and no ferrous Fe2+ form was observed. However, despite the indicated lack of changes in the iron oxidation state, the cationic substitution resulted in a significant increase in the magnetization and in a modification of the thermomagnetic curves. The magnetization values at 50 kOe were 34.5 emu/g at 4.2 K and 30.5 emu/g at 300 K. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves were measured in magnetic fields of 50 Oe, 100 Oe, 500 Oe and 1000 Oe, and revealed the presence of two magnetic phase transitions. Both transitions are shifted to higher temperatures compared to the undoped compound, while the ferrimagnetic arrangement at room temperature is transformed to a helical spin order at about 195 K, which is considered to be a prerequisite for the material to exhibit multiferroic properties.

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Section: Resultssupporting

confidence: 92%

Study of the Structural and Magnetic Properties of Co-Substituted Ba2Mg2Fe12O22 Hexaferrites Synthesized by Sonochemical Co-Precipitation

et al. 2019

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“…We also observed a different behavior of the ZFC curves for magnetic field strengths exceeding 500 Oe. The ZFC curves start decreasing upon reaching the helical ferrimagnetic phase transition and overlapping of the ZFC and FC curves occurs around 285 K. Kim and co-workers 54 showed that the temperature of a magnetic phase transition from helimagnetic spin ordering to ferromagnetic one in Ba 2 CoZnFe 12 O 22 decreased from 200 to 115 K when the magnetic Co 2+ cations were half-substituted by the nonmagnetic Zn 2+ cations. A detailed investigation of this phase transition for the Ba 2 Co 2– x Zn x Fe 12 O 22 system was reported in ref ( 55 ), but the second phase transformation from a helical to a longitudinal conical magnetic moments ordering was not seen in the entire ( x = 0–2) range.…”

Section: Magnetic Phase Transitionsmentioning

confidence: 99%

Phase Transitions in Magneto-Electric Hexaferrites

et al. 2022

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Hexaferrites have long been the object of extensive studies because of their great possibility for applications�permanent magnets, highdensity recording media, microwave devices, in biomedicine, to name but a few. Lately, many researchers' efforts have been focused on the existence of the magneto-electric effect in some hexaferrite systems and the appealing possibility of them being used as single-phase multiferroic and magnetoelectric materials. As indicated by theoretical analyses, the origin of the large magneto-electric effect can be sought in the strong interaction between the magnetization and the electric polarization that coexist in insulators with noncollinear magnetic structures. The hexaferrites' magnetic structure and, particularly, the specific magnetic spin ordering are the key factors in observing magneto-electric phases in hexaferrites. Some of these phases are metastable, which hampers their direct practical use. However, as the hexaferrites' phase diagrams reveal, chemical doping can be used to prepare a number of noncollinear stable magnetic phases. Since the magneto-electric effect has to do with the magnetic moments ordering, it seems only logical that one should study the cation substitutions' influence on the magnetic phase transition temperature. In this paper, we summarize recent examples of advances in the exploration of magnetic phase transitions in Y-type hexaferrites. In particular, the effect is emphasized by substituting in Y-type hexaferrites the nonmagnetic Me 2+ cations with magnetic ones and of the magnetic Fe 3+ cations with nonmagnetic ones on their magnetic properties and magnetic phase transitions. The work deals with the structural properties of and the magnetic phase transitions in a specific Y-type hexaferrite, namely, Ba(Sr) 2 Me 2 Fe 12 O 22 .

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