Abstract This research article reports the exploration of structural, dielectric, optical and electrical polarization properties of β-type hexagonal ferrite KLaxFe11-xO17 upon the substitution of rare earth element La3+ with compositions (x = 0, 0.02, 0.06 and 0.1). The samples were synthesized by adopting the sol-gel auto-combustion technique and the sintering temperature was 950 °C. The XRD patterns revealed the single hexagonal phase for all the samples. The lattice parameters a (A), c (A), crystallite size (nm), X-ray density (g/cm3) and unit cell volume V (A) 3 changed with La3+ substitution. The crystallite size was found to be varied in the range from 24 to 27 nm for all samples as calculated from Scherer formula. Fourier transform infrared spectroscopy (FTIR) spectra also confirmed the single phase for the synthesized samples. The dielectric constant exhibited the higher values than the pure sample with substitution. The dielectric constant results were fitted with the Debye function which indicated the participation of more than one ion in the increment of dielectric constant. The real (M′) and imaginary (M″) part of complex modulus graphs delineated the peaks shifting towards high and low frequency region which confirmed the occurrence of relaxation phenomenon in material. The polarization verses electric field loops corroborated the decrease in saturation and remnant polarization with La3+ contents. The P-E loops also showed the lossy behavior and the increment in lossy behavior with substitution pointed out the increase in resistivity of the samples. From aforementioned evidences, it is confirmed that the present synthesized beta ferrites are useful in the fabrication of humidity sensors and to reduce the eddy current losses.

中文翻译：

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La3+ 取代的 β-铁氧体：研究结构、介电、FTIR 和电极化特性

摘要 本研究文章报道了β型六方铁氧体KLaxFe11-xO17在用成分（x = 0、0.02、0.06和0.1）取代稀土元素La3+后的结构、介电、光学和电极化性质的探索。样品采用溶胶-凝胶自燃技术合成，烧结温度为950℃。XRD图谱显示所有样品均具有单一的六方相。晶格参数 a (A)、c (A)、微晶尺寸 (nm)、X 射线密度 (g/cm3) 和晶胞体积 V (A) 3 随 La3+ 取代而变化。根据 Scherer 公式计算，发现所有样品的微晶尺寸在 24 到 27 nm 的范围内变化。傅里叶变换红外光谱 (FTIR) 光谱也证实了合成样品的单相。介电常数表现出比具有取代的纯样品更高的值。介电常数结果与德拜函数拟合，这表明在介电常数的增加中参与了不止一种离子。复数模量图的实部 (M') 和虚部 (M") 描绘了向高频和低频区域移动的峰，这证实了材料中弛豫现象的发生。极化与电场回路的关系证实了饱和度和残余极化随 La3+ 含量的降低。PE 回路也显示出有损行为，替换后有损行为的增​​加表明样品的电阻率增加。从上述证据来看，