稀土鐵石榴石磁性電介質(zhì)陶瓷改性研究
發(fā)布時(shí)間：2018-10-10 12:55
【摘要】：稀土鐵石榴石磁性電介質(zhì)陶瓷因獨(dú)特的介電性能和磁光性能被廣泛用作微波器件材料和磁光記錄介質(zhì)；其介電常數(shù)在不同溫度和頻率下顯著變化,且外磁場可以改變其電容和介電常數(shù),石榴石陶瓷可調(diào)的介電性能使其在可調(diào)電容器和磁場傳感器等方面具有極大的應(yīng)用前景。本論文采用標(biāo)準(zhǔn)固相反應(yīng)法合成釔鐿鐵石榴石(Y3-xYbxFe5O12)陶瓷和釔鐿鐵鋁石榴石(Y3-xYbxFe4AlO12)陶瓷,分別研究c位稀土元素置換、c位稀土元素和d位Fe元素同時(shí)被置換對稀土鐵石榴石陶瓷性能的影響規(guī)律；同時(shí)合成鐿鉍石榴石(Yb3-xBixFe5O12)陶瓷,研究Bi3+部分置換Yb3+對其結(jié)構(gòu)和性能的影響。Y3-xYbxFe5O12(x=0,0.5,1,2,3)陶瓷在133K-573K范圍內(nèi)具有三個(gè)介電弛豫,yb3+部分置換Y3+對低溫弛豫激活能無明顯影響,降低了中溫介電弛豫激活能,顯著影響高溫介電弛豫激活能；Y3-xYbxFe5O12陶瓷飽和磁化強(qiáng)度受yb3+置換量影響很小；隨著Yb3+置換量的增加,Y3-xYbxFe5O12陶瓷的晶胞參數(shù)逐漸減小,Fe3+(a)-O-Fe3+(d)鍵角減小,導(dǎo)致五個(gè)組分樣品的Fe3+(a)-O-Fe3+(d)超交換作用逐漸減弱,表現(xiàn)為磁有序溫度的降低；隨著Yb3+置換量增加,Y3-xYbxFe5O12陶瓷的非本征磁介電效應(yīng)顯著弱化；Y3Fe5O12、Y2.5Ybo.5Fe5O12、Y2YbFe5O12三個(gè)組分中本征磁介電效應(yīng)占主導(dǎo)地位,三個(gè)組分樣品的磁介電系數(shù)隨著Yb3+含量增加而顯著增加；由于非本征磁介電效應(yīng)的極大消弱,YYb2Fe5O12、Yb3Fe5O12兩個(gè)組分磁介電系數(shù)顯著變小。Y3-xYbxFe4AlO12(x=0,0.5,1,2)陶瓷的飽和磁化強(qiáng)度和磁有序溫度取決于Fe3+(a)-O-Fe3+(d)超交換作用,Fe3+對超交換作用的影響占據(jù)主導(dǎo)地位,而稀土元素對其影響較小。Fe3+主要通過直接影響超交換作用對石榴石陶瓷的磁有序溫度和飽和磁感應(yīng)強(qiáng)度產(chǎn)生顯著影響；稀土元素主要通過改變晶胞參數(shù)進(jìn)而影響Fe3+(a)-O-Fe3+(d)鍵角,間接對石榴石陶瓷的磁有序溫度和飽和磁化強(qiáng)度產(chǎn)生影響；Y3-xYbxFe4AlO12陶瓷四個(gè)組分樣品中稀土元素置換對介電性能影響較小,而d位Fe3+置換對其電性能影響很大。Yb3-xBixFe5O12(x=0,0.5,1)陶瓷中Bi3+部分置換Yb3+使燒結(jié)溫度從1673K降低到1398K,同時(shí)其介電常數(shù)和介電損耗也顯著降低；Bi3+部分置換yb3+,Fe2+-Fe3+雙交換作用減弱,同時(shí)部分Fe3+偏離易磁化軸,導(dǎo)致其飽和磁化強(qiáng)度減��；Bi3+部分置換Yb3+使Fe3+(a)-O-Fe3+(d)超交換作用增強(qiáng),表現(xiàn)為磁介電系數(shù)減小和磁有序溫度增加。
[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.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ174.1
本文編號：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.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ174.1
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