Deng Li, Zhao Yang, Xie Zhaoming, Liu Zuohua, Tao Changyuan, Deng Rongrui
Chongqing Key Laboratory of Chemical Process for Clean Energy and Resource Utilization, Chongqing University Chongqing 400044 China
College of Chemistry and Chemical Engineering, Chongqing University Chongqing 400044 China.
RSC Adv. 2018 Dec 17;8(73):42009-42016. doi: 10.1039/c8ra08783k. eCollection 2018 Dec 12.
In the present work, to enhance the reflection loss and change the magnetic resonance frequency of barium ferrite sintered at low temperature, different amounts of Zr ion were introduced to BaFeO to substitute the Fe ion. A series of M-type barium hexaferrite samples having the nominal composition BaZr FeO ( = 0.0, 0.3, 0.6, 0.9 and 1.2) was successfully synthesized by heat treatment at a relatively low temperature (900 °C) for 2 h. In order to study the phases, morphologies and magnetic properties of the substituted barium ferrites, X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM) were used. The XRD patterns indicated that all samples were single phase M-type ferrites. The SEM images showed that all samples were hexagonal-shaped particles and the average size was about 500 nm. Simultaneously, a potassium chloride additive can effectively reduce the sintering temperature of barium ferrites and their formation and morphology are apparently not affected. The VSM results demonstrated that the coercivity steeply decreased from 4772.43 Oe to 797.34 Oe when the Zr ion substitution amount increased from 0.0 to 1.2 but the saturation magnetization remained almost constant ( = 49.71-63.06 emu g). Furthermore, the complex electromagnetic parameters were collected by a vector network analyzer (VNA) and the microwave absorbing properties were calculated according to transmission theory. It was found that the reflection loss is enhanced with increasing . The minimum reflection loss value of -30.2 dB at 16.75 GHz was observed and the bandwidth is about 2.46 GHz for the = 1.2 sample. BaZr FeO might be a promising candidate for applications of LTCC (low-temperature co-fired ceramic) substrates for millimeter wave circulators and filters.
在本工作中，为了提高低温烧结钡铁氧体的反射损耗并改变其磁共振频率，将不同量的Zr离子引入BaFeO中以替代Fe离子。通过在相对较低温度（900℃）下热处理2小时，成功合成了一系列标称组成为BaZrₓFe₁₂₋ₓO₁₉（x = 0.0、0.3、0.6、0.9和1.2）的M型钡铁氧体样品。为了研究取代钡铁氧体的相、形貌和磁性能，使用了X射线衍射（XRD）、扫描电子显微镜（SEM）和振动样品磁强计（VSM）。XRD图谱表明所有样品均为单相M型铁氧体。SEM图像显示所有样品均为六边形颗粒，平均尺寸约为500nm。同时，氯化钾添加剂可有效降低钡铁氧体的烧结温度，且其形成和形貌明显不受影响。VSM结果表明，当Zr离子取代量从0.0增加到1.2时，矫顽力从4772.43 Oe急剧下降到797.34 Oe，但饱和磁化强度几乎保持不变（Ms = 49.71 - 63.06 emu g）。此外，通过矢量网络分析仪（VNA）收集复电磁参数，并根据传输理论计算微波吸收性能。发现反射损耗随x的增加而增强。对于x = 1.2的样品，在16.75 GHz处观察到最小反射损耗值为-30.2 dB，带宽约为2.46 GHz。BaZrₓFe₁₂₋ₓO₁₉可能是用于毫米波环行器和滤波器的低温共烧陶瓷（LTCC）基板应用的有前途的候选材料。
