Magneto-optical properties of SrBi_xLa_xFe_12-2xO₁₉ (0.0≤x≤0.5) hexaferrites by sol-gel auto-combustion technique

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• 作者：I.A. Auwal^a ; ^b ; ; A. Baykal^b ; S. Gü ; ner^c ; H. Sö ; zeri^d
• 关键词：Strontium hexaferrite ; Optical properties ; Magnetic properties ; Sol-gel synthesis
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1298-1303
• 全文大小：912 K

文摘

SrBi_xLa_xFe_12-2xO₁₉ (0.0≤x≤0.5) hexaferrites were synthesized by sol-gel auto combustion technique. The influence of Bi and La substitutions on structural, magnetic and optical properties were investigated by X-ray diffraction (XRD), Furrier transformed infrared (FT-IR), Vibrating sample magnetometer (VSM) and Percent diffuse reflectance spectroscopy (DR %). XRD analysis confirmed the single phase formation for all the samples, the purity of the products was also confirmed by FT-IR. The specific magnetization (σ-H) curves revealed the ferromagnetic nature of the samples. The extrapolated specific saturation magnetization (σ_s) decreases from 63.45 emu/g to 49.84 emu/g with increasing Bi, La substitutions. Similar decrement is observed from 32.6 emu/g to 25.8 emu/g at remnant magnetization (σ_r). The average crystallite size varies in a range of (43.28–51.40) nm. The coercive fields are between 4682 and 5315 Oe. Magnetic anisotropy was assigned as uniaxial and calculated effective anisotropy constants (K_eff) are between 5.57×10⁵ Ergs/g and 4.03×10⁵ Ergs/g. The observed high magnitudes of intrinsic coercivity (H_ci) above 16,000 Oe confirm hard magnetic nature of the samples. The Tauc plots were used to extrapolate the direct optical energy band gap (E_g) of hexaferrites. The E_g values decreased from 1.81 to 1.68 eV with increasing Bi, La contents.