Hydrothermal synthesis and competitive growth of flake-like M-type strontium hexaferrite

Abstract

In this paper, single flake-like strontium hexaferrite was directly synthesized via a modified hydrothermal approach without high-temperature annealing. To determine the main factors governing the formation of the hexaferrite phase and impurity a-Fe 2 O 3 , effects of alkali environment and concentrations of metal ions on phase composition, grain growth, and magnetic properties were systematically analyzed. Results from XRD, FESEM and FT-IR analyses indicated that initial alkali concentration was the key factor influencing the phase composition of particles. Suitable initial alkali environment can enhance the nucleation and growth of ferrite, and inhibit the formation of by-product a-Fe 2 O 3 at the same time. It was also found that the increase in initial concentration of strontium ions could improve the nucleation of hexaferrite and reduce the grain size, and consequently, change the magnetic performance of hexagonal particles. When the molar ratios of ferric ions to strontium ions were constant, the average grain size did not change significantly with the initial concentration of iron ions, which could be attributed to high levels of strontium ions and hydroxyl ions in the reaction system. The abovementioned results indicate that the optimized hydrothermal conditions are beneficial for the formation of a single phase and for controlling the particle size and magnetic properties of M-type hexaferrite.

Retracted Article: Wavelength modulation of ZnO nanowire based organic light-emitting diodes with ultraviolet electroluminescence

“…A 10 nm ZnO seed layer was sputtered onto the pre-cleaned ITO glass followed by growing ZnO NWs using a hydrothermal method. [33][34][35] The polyethylenimine (PEI) material was spin-coated from a 0.4 wt% 2-methoxyethanol solution (5000 rpm, 50 seconds). 36 Then, the lms were thermally annealed in an ambient environment for 10 minutes at a temperature of 100 C. Aer thermal annealing, 3-(4biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ) as an emission layer and 2,9-dimethyl-4,7-dipheny-l-1,10-phenanthroline (CBP) as a hole transport layer were thermally evaporated on PEI layer, respectively.…”

Surfactant assisted synthesis of strontium hexaferrite microspheres for the fabrication of high-performance asymmetric supercapacitors

“…8A). 35 The spectrum of Sr 3d shown in Fig. 8B displayed two peaks at binding energies of 134.6 and 136.1 eV, which correspond to Sr 3d 5/2 and Sr 3d 3/2 levels, respectively.…”

Structural, ferromagnetic, ferroelectric, and bio-medical behaviour of yttrium doped strontium hexaferrite (SrFe12-xYxO19) nano materials, assisted with sol-gel cost effective technique

“…In hexaferrite, the absorbance peak obtained at 438 cm −1 is related to octahedral locations in the unit cell whereas the absorbance peak at 597 cm −1 signifies a tetrahedral site. Octahedral bond length is quantified by the frequency region 418-438 cm −1 [33]. While frequency region 585-601 cm −1 is helpful in determining the tetrahedral bond length of (Fe-O), and (Sr-O) [34].…”