La_(1-x)K_xMnO_3的微波吸收特性  

Microwave absorption properties of La_(1-x)K_xMnO_3

作　　者：黄生祥[1] 齐伟[1] 周克省[1] 秦宪明 陈颖[1] 邓联文[1] 夏辉[1] 韩建华[1] 

机构地区：[1]中南大学物理与电子学院,长沙410083 [2]厦门市宏业工程建设技术有限公司,厦门361001

出　　处：《中国有色金属学报》2012年第2期448-452,共5页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(60771028);湖南省自然科学基金资助项目(10JJ5049);湖南省科技计划资助项目(2011SK3258);湖南省高校重点实验室基金资助项目(311101049);粉末冶金国家重点实验室开放基金资助项目

摘　　要：用溶胶-凝胶法制备La1-xKxMnO3粉晶,用X射线衍射仪和扫描电镜表征样品的晶体结构和微观形貌,用微波矢量网络分析仪测试了该样品在2~18 GHz微波频率范围的复介电常数和复磁导率,并计算损耗角正切及微波反射率,分析K掺杂量和样品厚度对体系微波吸收性能的影响及微波损耗机制。结果表明：晶体结构为钙钛矿型,颗粒形貌为不规则椭球状或短棒状;当样品厚度为2.40 mm、x=0.3时,吸收峰值为27.1 dB,10 dB以上有效吸收频带宽度达10.6 GHz。纳米La1-xKxMnO3兼具介电损耗和磁损耗,介电损耗相对较强。磁损耗因子和介电损耗因子随微波频率的变化相反,是基体中铁磁与反铁磁团簇在微波电磁场作用下相互转变引起。The La1-xKxMnO3 powders were prepared by so1-gel method.The crystal structure and surface morphologies of the particles were characterized by X-ray diffractometry and scanning electron microscopy,respectively.The complex dielectric constant and complex permeability were measured by microwave vector network analyzer in the frequency range from 2 to 18 GHz,and the reflection coefficient and loss tangent were calculated according to measurements.The results show that the crystal structure of La1-xKxMnO3 is perovskite and its crystal powder morphology is irregular ellipsoidal shape or short rod,and the absorption peak is 27 dB and the bandwidth above 10 dB is 10.6 GHz when the thickness of the sample is 2.40 mm（x=0.3）.Nano-La1-xKxMnO3 has both dielectric loss and magnetic loss,but the former is relatively stronger.Due to the mutual transformation between ferromagnetic and antiferromagnetic clusters of the matrix in the microwave electromagnetic field,the magnetic and dielectric loss tangent changes inversely with the changes of microwave frequency.

关 键 词：La1-xKxMnO3 微波吸收 电磁损耗 钙钛矿 

分 类 号：O441.6[理学—电磁学]