FIR optical properties of single crystal Ba-and Sr-hexaferrite

Nikolić, P.M.; Zivanov, L.J.D.; Aleksić, O.S.; Samaras, D.; Gledhill, G. A.; Collins, John D.

doi:10.1016/0020-0891(90)90008-j

Cited by 11 publications

(16 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another striking feature of the sample at 873 K is the breadth of the spectra in the region 650–550 cm −1 , where some bands are certainly lost because of their partial superimpostion and, probably, their greater width. The phenomenon was explained to be the result of the dynamic disorder of Fe(5) ions, distributed between the 2d “in‐plane” sites and the two 4e “out‐of‐plane” sites in a hexaferrite lattice by Bellotto et al 34 and Nicolic et al 39 Thus, it can be concluded that the disordered hexaferrite skeletal formed at 873 K. In addition, the bands near 856 and 692 cm −1 for the sample at 873 K weakened, which was due to the decomposition of the carbonate. Bellotto et al 34 had identified the bands in the region 150–50 cm −1 with the vibration of Ba 2+ cations in BaM, and assigned the lower energy mode 102 cm −1 to E u vibration and the higher 124 cm −1 to A 2u .…”

Section: Resultsmentioning

confidence: 99%

FTIR Spectra, Lattice Shrinkage, and Magnetic Properties of CoTi‐Substituted M‐Type Barium Hexaferrite Nanoparticles

Zhao

Wei

Cheng

et al. 2007

Journal of the American Ceramic Society

View full text Add to dashboard Cite

Single‐phase BaCoTiFe10O19 (BaCoTi‐M) nanoparticles were prepared by a modified sol–gel process, using metallic chlorides as starting materials. The physical chemistry process of BaCoTi‐M formation, the interdependences between composition, technological conditions, microstructure, and magnetic properties were studied by X‐ray diffraction (XRD), Fourier transform‐infrared (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). XRD and FTIR results show that BaCoTi‐M nanoparticles formed directly from γ‐Fe2O3, spinel ferrite, and barium salts without the formation of α‐Fe2O3 and BaFe2O4. The lattice shrinkage of BaCoTi‐M nanoparticles that occurred on increasing the calcining temperature from 973 to 1173 K under holding for 2 h or on increasing the holding time in the range 0–2 h at 1173 K was discovered by analyzing the dependences of lattice parameters on the heat‐treatment conditions. The shrinkage led to a relatively higher concentration of magnetic Fe3+ cations in the unit cell, and resulted in an increase of specific saturation magnetization under the corresponding conditions. Microstructural characterization shows that the evolutions of coercivity, remnant magnetization, and squareness ratio depended on the crystal growth and the reduction of structural defect as well as a decrease of grain boundary.

show abstract

Section: Resultsmentioning

confidence: 99%

FTIR Spectra, Lattice Shrinkage, and Magnetic Properties of CoTi‐Substituted M‐Type Barium Hexaferrite Nanoparticles

Zhao

Wei

Cheng

et al. 2007

Journal of the American Ceramic Society

View full text Add to dashboard Cite

show abstract

“…Therefore, it is useful to discuss the BaM IR spectra reported in the literature. The IR spectra of BaM reported by Nicolic et al (4,5) exhibit three bands at low frequency: two bands of A S symmetry at 59 and 124 cm\ and one band of E S symmetry at 95 cm\. Belotto et al (7) found for BaM two low-frequency bands at 102 and 124 cm\ and assigned both to vibrations of the Ba> cation.…”

Section: Comparison and Assignmentmentioning

confidence: 95%

“…Another interesting point concerning the IR data of Nicolic et al (4,5) is the observed splitting of TO-and LOfrequency for a given mode. In general, the magnitude of the splitting gives an approximated order of the degree of ionicities.…”

Section: Comparison and Assignmentmentioning

confidence: 96%

“…There is still controversy about the symmetry of the vibrational modes in the literature (4)(5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

“…Polarized far-infrared reflection spectra have been used to investigate the optical and dielectric properties (4,5). Eremenko et al (6) studied infrared (IR) reflection spectra of cooled BaM single crystals.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations