稀土铁石榴石磁性电介质陶瓷改性研究
发布时间：2018-10-10 12:55
【摘要】：稀土铁石榴石磁性电介质陶瓷因独特的介电性能和磁光性能被广泛用作微波器件材料和磁光记录介质；其介电常数在不同温度和频率下显著变化,且外磁场可以改变其电容和介电常数,石榴石陶瓷可调的介电性能使其在可调电容器和磁场传感器等方面具有极大的应用前景。本论文采用标准固相反应法合成钇镱铁石榴石(Y3-xYbxFe5O12)陶瓷和钇镱铁铝石榴石(Y3-xYbxFe4AlO12)陶瓷,分别研究c位稀土元素置换、c位稀土元素和d位Fe元素同时被置换对稀土铁石榴石陶瓷性能的影响规律；同时合成镱铋石榴石(Yb3-xBixFe5O12)陶瓷,研究Bi3+部分置换Yb3+对其结构和性能的影响。Y3-xYbxFe5O12(x=0,0.5,1,2,3)陶瓷在133K-573K范围内具有三个介电弛豫,yb3+部分置换Y3+对低温弛豫激活能无明显影响,降低了中温介电弛豫激活能,显著影响高温介电弛豫激活能；Y3-xYbxFe5O12陶瓷饱和磁化强度受yb3+置换量影响很小；随着Yb3+置换量的增加,Y3-xYbxFe5O12陶瓷的晶胞参数逐渐减小,Fe3+(a)-O-Fe3+(d)键角减小,导致五个组分样品的Fe3+(a)-O-Fe3+(d)超交换作用逐渐减弱,表现为磁有序温度的降低；随着Yb3+置换量增加,Y3-xYbxFe5O12陶瓷的非本征磁介电效应显著弱化；Y3Fe5O12、Y2.5Ybo.5Fe5O12、Y2YbFe5O12三个组分中本征磁介电效应占主导地位,三个组分样品的磁介电系数随着Yb3+含量增加而显著增加；由于非本征磁介电效应的极大消弱,YYb2Fe5O12、Yb3Fe5O12两个组分磁介电系数显著变小。Y3-xYbxFe4AlO12(x=0,0.5,1,2)陶瓷的饱和磁化强度和磁有序温度取决于Fe3+(a)-O-Fe3+(d)超交换作用,Fe3+对超交换作用的影响占据主导地位,而稀土元素对其影响较小。Fe3+主要通过直接影响超交换作用对石榴石陶瓷的磁有序温度和饱和磁感应强度产生显著影响；稀土元素主要通过改变晶胞参数进而影响Fe3+(a)-O-Fe3+(d)键角,间接对石榴石陶瓷的磁有序温度和饱和磁化强度产生影响；Y3-xYbxFe4AlO12陶瓷四个组分样品中稀土元素置换对介电性能影响较小,而d位Fe3+置换对其电性能影响很大。Yb3-xBixFe5O12(x=0,0.5,1)陶瓷中Bi3+部分置换Yb3+使烧结温度从1673K降低到1398K,同时其介电常数和介电损耗也显著降低；Bi3+部分置换yb3+,Fe2+-Fe3+双交换作用减弱,同时部分Fe3+偏离易磁化轴,导致其饱和磁化强度减小；Bi3+部分置换Yb3+使Fe3+(a)-O-Fe3+(d)超交换作用增强,表现为磁介电系数减小和磁有序温度增加。
[Abstract]:Rare earth iron garnet magnetic dielectric ceramics are widely used as materials for microwave devices and magneto-optical recording media due to their unique dielectric properties and magneto-optical properties, and their dielectric constants vary significantly at different temperatures and frequencies. The external magnetic field can change its capacitance and dielectric constant. The tunable dielectric properties of garnet ceramics make it have a great application prospect in tunable capacitors and magnetic field sensors. Yttrium ytterbium iron garnet (Y3-xYbxFe5O12) and yttrium ytterbium iron aluminum garnet (Y3-xYbxFe4AlO12) ceramics were synthesized by standard solid state reaction. The effects of substitution of c rare earth elements and d Fe elements on the properties of rare earth iron garnet ceramics were studied, and ytterbium bismuth garnet (Yb3-xBixFe5O12) ceramics were synthesized. The effect of partial replacement of Bi3 Yb3 on the structure and properties of Y3-xYbxFe5O12 ceramics was studied. Y3-xYbxFe5O12 (x0. 0. 5) ceramics have three dielectric relaxations in the range of 133K-573K, and yb3 partial replacement of Y3 has no obvious effect on the activation energy of low temperature relaxation, which reduces the activation energy of dielectric relaxation at moderate temperature. The activation energy of dielectric relaxation at high temperature was significantly affected, the saturation magnetization of Y3-xYbxFe5O12 ceramics was little affected by the amount of yb3 replacement, and the unit cell parameters of Y3-xYbxFe5O12 ceramics gradually decreased and the Fe3 (a) O-Fe3 (d) bond angle decreased with the increase of Yb3 replacement amount. As a result, the superexchange effect of Fe3 (a)-O-Fe3 (d) in the five component samples is gradually weakened, which is characterized by the decrease of the magnetic ordering temperature, and the weakening of the intrinsic magnetic dielectric effect of Y3-xYbxFe5O12 ceramics with the increase of the Yb3 replacement amount. The intrinsic magnetic dielectric effect of Y _ 3FE _ 5o _ (12) O _ (12) Y2.5Yb 路5Fe _ (5) O _ (12) is dominant, and the magnetic dielectric coefficient of the three components increases with the increase of Yb3 content. The magnetic dielectric coefficient of the two components of YYb2Fe5O12,Yb3Fe5O12 decreases significantly due to the great weakening of the extrinsic magnetic dielectric effect. The saturation magnetization and the magnetic ordering temperature of Y3-xYbxFe4AlO12 (x0 / 0 / 0.51 / 2) ceramics depend on the superexchange effect of Fe3 (a)-O-Fe3 (d), and the influence of Fe3 on the superexchange is dominant. However, rare earth elements have little effect on them. Fe3 has a significant effect on the magnetic order temperature and saturation magnetic induction intensity of garnet ceramics by directly affecting the superexchange effect, and the rare earth elements mainly affect the Fe3 (a) O-Fe3 (d) bond angle by changing the unit cell parameters. Indirect influence on magnetic order temperature and saturation magnetization of garnet ceramics, rare earth element replacement has little effect on dielectric properties of Y3-xYbxFe4AlO12 ceramics. The d position Fe3 replacement has a great effect on the electrical properties. The Bi3 partial replacement Yb3 in Yb3-xBixFe5O12 (X0. 0. 0. 5) ceramics reduces the sintering temperature from 1 673 K to 13 98 K, and the dielectric constant and dielectric loss also decrease significantly, while the Bi3 partial replacement yb3, Fe2-Fe3 double exchange interaction weakens. At the same time, some Fe3 deviates from the easy magnetization axis, which leads to the decrease of saturation magnetization, and the partial replacement of Bi3 Yb3 enhances the Fe3 (a) O-Fe3 (d) superexchange interaction, which is characterized by the decrease of magnetic dielectric coefficient and the increase of magnetic ordering temperature.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1
本文编号：2261848
[Abstract]:Rare earth iron garnet magnetic dielectric ceramics are widely used as materials for microwave devices and magneto-optical recording media due to their unique dielectric properties and magneto-optical properties, and their dielectric constants vary significantly at different temperatures and frequencies. The external magnetic field can change its capacitance and dielectric constant. The tunable dielectric properties of garnet ceramics make it have a great application prospect in tunable capacitors and magnetic field sensors. Yttrium ytterbium iron garnet (Y3-xYbxFe5O12) and yttrium ytterbium iron aluminum garnet (Y3-xYbxFe4AlO12) ceramics were synthesized by standard solid state reaction. The effects of substitution of c rare earth elements and d Fe elements on the properties of rare earth iron garnet ceramics were studied, and ytterbium bismuth garnet (Yb3-xBixFe5O12) ceramics were synthesized. The effect of partial replacement of Bi3 Yb3 on the structure and properties of Y3-xYbxFe5O12 ceramics was studied. Y3-xYbxFe5O12 (x0. 0. 5) ceramics have three dielectric relaxations in the range of 133K-573K, and yb3 partial replacement of Y3 has no obvious effect on the activation energy of low temperature relaxation, which reduces the activation energy of dielectric relaxation at moderate temperature. The activation energy of dielectric relaxation at high temperature was significantly affected, the saturation magnetization of Y3-xYbxFe5O12 ceramics was little affected by the amount of yb3 replacement, and the unit cell parameters of Y3-xYbxFe5O12 ceramics gradually decreased and the Fe3 (a) O-Fe3 (d) bond angle decreased with the increase of Yb3 replacement amount. As a result, the superexchange effect of Fe3 (a)-O-Fe3 (d) in the five component samples is gradually weakened, which is characterized by the decrease of the magnetic ordering temperature, and the weakening of the intrinsic magnetic dielectric effect of Y3-xYbxFe5O12 ceramics with the increase of the Yb3 replacement amount. The intrinsic magnetic dielectric effect of Y _ 3FE _ 5o _ (12) O _ (12) Y2.5Yb 路5Fe _ (5) O _ (12) is dominant, and the magnetic dielectric coefficient of the three components increases with the increase of Yb3 content. The magnetic dielectric coefficient of the two components of YYb2Fe5O12,Yb3Fe5O12 decreases significantly due to the great weakening of the extrinsic magnetic dielectric effect. The saturation magnetization and the magnetic ordering temperature of Y3-xYbxFe4AlO12 (x0 / 0 / 0.51 / 2) ceramics depend on the superexchange effect of Fe3 (a)-O-Fe3 (d), and the influence of Fe3 on the superexchange is dominant. However, rare earth elements have little effect on them. Fe3 has a significant effect on the magnetic order temperature and saturation magnetic induction intensity of garnet ceramics by directly affecting the superexchange effect, and the rare earth elements mainly affect the Fe3 (a) O-Fe3 (d) bond angle by changing the unit cell parameters. Indirect influence on magnetic order temperature and saturation magnetization of garnet ceramics, rare earth element replacement has little effect on dielectric properties of Y3-xYbxFe4AlO12 ceramics. The d position Fe3 replacement has a great effect on the electrical properties. The Bi3 partial replacement Yb3 in Yb3-xBixFe5O12 (X0. 0. 0. 5) ceramics reduces the sintering temperature from 1 673 K to 13 98 K, and the dielectric constant and dielectric loss also decrease significantly, while the Bi3 partial replacement yb3, Fe2-Fe3 double exchange interaction weakens. At the same time, some Fe3 deviates from the easy magnetization axis, which leads to the decrease of saturation magnetization, and the partial replacement of Bi3 Yb3 enhances the Fe3 (a) O-Fe3 (d) superexchange interaction, which is characterized by the decrease of magnetic dielectric coefficient and the increase of magnetic ordering temperature.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1
【参考文献】
相关期刊论文 前2条
1 任清褒;固态电介质的物理特性及其应用前景[J];材料科学与工程学报;2003年06期
2 ZHANG Min;LIU QiangChun;ZI ZhenFa;DAI YuQiang;ZHU XueBin;SUN YuPing;DAI JianMing;;Magnetic and microwave absorption properties of Ni_(1-x)Zn_xFe_2O_4 nanocrystalline synthesized by sol-gel method[J];Science China(Technological Sciences);2013年01期
相关博士学位论文 前1条
1 王鑫;高压下铁磁性物质磁性测量系统的研究[D];吉林大学;2014年
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