Fe/Sr ratio and calcination temperature effects on processing of nanostructured strontium hexaferrite thin films by a sol–gel method

Abstract

Nanostructured single-phase strontium hexaferrite, SrFe 12 O 19 (SrM), thin films have been synthesized successfully for the first time on silicon substrates using a spin-coating sol-gel process. The precursor solution was prepared from metal nitrates, citric acid, and ethylene glycol. The thin films with various Fe/Sr molar ratios of 8-12 were heat treated at different temperatures from 700 to 900°C. The composition, microstructure, and magnetic properties of the SrM thin films were also characterized. The results showed that the optimum molar ratio for Fe/Sr was 10, at which the lowest calcination temperature for obtaining the single-phase strontium hexaferrite thin films was 800°C. The crystallite size of the resultant thin films was below 50 nm.

Factors affecting formulation characteristics and stability of ascorbic acid in water‐in‐oil creams

“…Similarly, it gives a stretching band at 1730 cm À1 for C=O, 1625 and 1400 cm À1 for COO À vibration and stretching, respectively, 1200 cm À1 for C-O stretching or OH deformation and 940 cm À1 for out-of-plane OH bending ( Fig. 4) [69,70]. The FTIR spectra of the physical mixtures of AA and CT in 1 : 1, 1 : 2 and 2 : 1 ratios are shown in Fig.…”

Developing a new production process for high-porosity lactose particles with high degrees of crystallinity

“…The characteristic band for crystalline α-lactose monohydrate appears at 920 cm -1 , and those for β-lactose at 950 cm -1 and 833 cm -1 [41,42]. The spectrum of the pure citric acid solution has a stretching band at 1,625 cm -1 attributed to the C=O in the dissociated carboxylic acid, while it is 1,730 cm -1 when not dissociated [43,44]. The measurements have been conducted at least five times.…”

EFFECT OF pH VALUE AND CALCINATION TEMPERATURE ON STRUCTURE AND MAGNETIC PROPERTIES OF STRONTIUM HEXAFERRITE THIN FILM

“…1,18 Actually, the strontium hexaferrite crystals at calcination temperatures of 800 C and 1000 C gather directionally along the special crystallographic axis, leading to an increase in the anisotropy of the crystal; the magnetic properties increase with the increase of the strontium hexaferrite crystal anisotropy. 17 Therefore, the coercivity and the magnetization for the coatings were found to be improved by increasing calcination temperature.…”

“…16,17 Figure 2 shows the X-ray diffraction pattern of strontium hexaferrite coatings which calcinated at three different temperatures, such as 600 C, 800 C, and 1000 C, under controlled atmosphere. The pattern shows well defined Bragg peaks at 600 C, 800 C, and 1000 C, which are significant of a good crystalline state of the samples.…”

“…Thus, more homogeneous solution is obtained, resulting in the easy formation of strontium ferrite. 17 The magnetic properties of strontium hexaferrite thin films at three different pH values were measured by using a VSM and are given in Table 1. The coercivity (Hc) for the thin films first increased and then decreased with an increase of pH value.…”