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1.
秦媛  刘毅  胡林  张羽琴 《硅酸盐学报》2011,(10):1581-1584
采用溶胶-凝胶的方法制备了Bi0.75Sr0.25MnO3化合物,并对其结构、磁性质、铁电性进行了研究。X射线衍射结果显示样品为单相钙钛矿结构,电阻率和差热实验证实了样品在590K的温度附近发生了电荷有序相变。磁性质测量表明样品在低温下(5K)为铁磁性。电滞回线测量显示样品在室温下最大的剩余极化强度Pr为4.47×10...  相似文献   

2.
多铁性磁电材料应用于存储技术的研究现状   总被引:2,自引:0,他引:2  
施科  何泓材  王宁 《硅酸盐学报》2011,39(11):1792-1799
多铁性磁电材料同时具有铁电性、铁磁性和磁电效应等多种性能,它为新功能存储器件的设计提供了可能性。主要综述了多铁性磁电单相和复合材料在存储技术领域的应用研究,包括基于多铁性磁电材料设计的"电写磁读"多铁性磁电存储器、多态存储器以及基于多铁性磁电材料设计双稳态储存器件的新原理和新思路;介绍了多铁性磁电材料在存储读头技术方面...  相似文献   

3.
溶胶-凝胶法制备了BiFe0.95Co0.05O3、Bi0.95 Pr0.05FeO3和Bi0.95Pr0.05Fe0.95Co0.05O3样品。X射线衍射仪、铁电分析仪和振动样品磁强计测量与分析了样品结构、铁电和铁磁性能。结果表明:共掺杂的样品磁性有所增强,这与样品的结构变化有关。Pr掺杂提高了材料的铁电性能,这是因为Pr掺杂减少了氧空位。  相似文献   

4.
采用固相合成法分别制备了尖晶石结构Co Fe_2O_4和钙钛矿结构Ba Ti O_3粉末,烧结得到x Co Fe_2O_4/(1―x)Ba Ti O_3(x=0.2,0.4,0.6,0.8)复相多铁材料,对材料的成分、介电性能、铁电性、磁性能进行了表征。结果表明:当x=0.2时所得的复相多铁材料两相共存,无杂相,而其他组分均不同程度地存在杂相。复相多铁材料x Co Fe_2O_4/(1―x)Ba Ti O_3具有铁电性和铁磁性,且性能受铁磁相含量影响明显。随铁磁相组分增加,材料介电常数变小,漏电流增大,铁电性能变差;同时,铁磁相间颗粒接触面积增大,磁化作用得到加强,材料磁性能得到提升。  相似文献   

5.
综述了多铁性材料的发展,介绍了单相多铁性材料和复合多铁性材料的特点、改善单相多铁性材料和复合多铁性材料性能的途径,并对其发展前景进行了展望。  相似文献   

6.
多铁性材料是指材料的同一个相中包含两种及两种以上铁的基本性能.详细分析了两种类型的单相磁电材料的微观结构,并讨论了复合磁电材料的制备方法.  相似文献   

7.
多铁性材料是指材料的同一个相中包含两种及两种以上铁的基本性能。本文从形成多铁性材料所具备的条件、典型的晶体结构类型、多铁性材料中的相控制和多铁性产生的机制四个方面对多铁性材料作了介绍,并对多铁性材料的发展作了展望。  相似文献   

8.
采用溶胶-凝胶法分别在空气和N2气气氛中不同烧成时间下制备了均匀致密度的SUS430合金LSM涂层.观察了不同气氛下烧结3h的涂层样品的SEM表面形貌;采用四点法测量了不同气氛和不同烧成时间下制备的各涂层样品的ASR值,测量分析了各涂层样品在800℃下空气中热处理120h过程中的氧化增重量变化.结果表明,N2气气氛下烧成的涂层比空气气氛下烧结的涂层烧结程度更好、ASR值更低,并具有更好的抗氧化保护作用;空气气氛下烧成时间对涂层的烧结程度、导电性能和抗氧化性能影响显著,N2气气氛下烧成时间对涂层的烧结程度、导电性能和抗氧化性能影响不大.  相似文献   

9.
双钙钛矿型室温多铁性材料的研究进展   总被引:1,自引:1,他引:1  
石雷  白飞明 《硅酸盐学报》2011,39(3):550-558
从多铁性材料和磁电耦合效应出发,介绍了双钙钛型室温单相磁电多铁性材料的研究进展,包括典型的Bi2(NiMn)O6、Bi2(CoMn)O6和Bi2(FeCr)O6块体材料和外延薄膜材料,在此基础上结合BiFeO3讨论了双钙钛矿结构材料存在的一些关键问题,最后对这些问题的解决提出了展望.  相似文献   

10.
磁电多铁性材料中电荷和自旋序参量共存,并相互耦合在一起,产生磁电耦合效应。由于磁电耦合效应在未来高密度、低能耗、高读写速率器件的重要应用前景,近10年来,多铁性材料的研究成为了材料科学以及凝聚态物理领域的热点之一。BiFeO3不仅是为数不多的铁电反铁磁的多铁性材料之一,更难能可贵的是它的铁电Curie温度和反铁磁Néel温度都远高于室温。正因为如此,BiFeO3早在60多年前就受到人们的关注;但是直到2003年高质量外延薄膜的出现,才真正掀起了人们对其卓越性能和新奇物理现象研究的热潮。正是在这个背景下回顾BiFeO3的发展历史,着重介绍近10年此领域的研究成果:从晶体结构、电学性质(巨大铁电极化、电致阻变效应等)、磁学性质(自旋螺旋结构)以及磁电耦合特性等角度,对由BiFeO3多铁性模型体系中衍生出来的新奇物理现象进行详细介绍。最后,就近几年相关领域的研究进行总结和研究展望。  相似文献   

11.
We report a power conversion efficiency of ~0.01% in multistacking of BiFeO3/BiCrO3 bilayer thin films used as active layers in a photovoltaic (PV) device. The films were epitaxially deposited by pulse laser deposition onto (100) oriented CaRuO3‐coated LaAlO3 substrates and were subsequently illuminated with 1 sun (AM 1.5). The fill factor is determined to be 0.31%, a remarkable value for ferroelectric‐ and multiferroic‐based PV devices. Our results demonstrate that photocurrent density and photovoltage can be tuned by varying the thickness and number of respective bilayers in the improvement of PV properties of multiferroic heterostructures. The maximum photocurrent is generated at an optimal multilayer thickness of 60 nm, with its origin being mainly ascribed to the contribution of ferroelectric polarization.  相似文献   

12.
Mutiferroic materials like bismuth ferrite BiFeO3 have attracted much interest in the last decade due to their promising potential for such applications as spintronics and magnetoelectric data storage devices. On the other hand, relaxor ferroelectrics have been intensively studied for their complex structures with quenched disorder and polar nanoregions which play an important role in their outstanding piezoelectric performance. Much less studied are the single-phase multiferroics that exhibit ferroelectric and/or magnetic relaxor behavior and the correlation between their structure and intricate magneto-electric interactions. In this work, we investigate the evolution of the structure and relaxor behavior in the solid solution between the complex perovskite multirelaxor Pb(Fe2/3W1/3)O3 [PFW] and canonical multiferroic BiFeO3 [BFO], (1-x)PFW-xBFO (with a solubility limit of x = 0.30). The temperature dependences of the dielectric permittivity and loss tangent measured in the frequency range from 100 Hz to 1 MHz indicate characteristic relaxor ferroelectric properties for compositions of x ≤ 0.15, with a frequency-dependent dielectric permittivity peak and its temperature, Tm, satisfying the Vogel-Fulcher law. Detailed studies of the evolution of the relaxor behavior with composition reveal that Tm decreases firstly with a small amount (x = 0.05) of BFO substitution and then increases with further increase of BFO concentration. The degree of relaxor character, as defined by ΔTm [Tm (1 MHz) - Tm (100 Hz)], increases monotonously with increasing BFO content, signifying an enhancement of relaxor behavior with BFO substitution, which is confirmed by the Lorenz-type quadratic variation of the static permittivity. A temperature - composition phase diagram is constructed in terms of the characteristic Burns temperature (TB) and freezing temperature (Tf), which delimits a paraelectric state (PE) above TB, a non-ergotic relaxor state (NR) below Tf, and an ergotic relaxor state (ER) in between. The observed enhancement of relaxor behavior is explained by an increase in the number and size distribution of polar nanoregions in the ER phase, resulting from increased compositional and charge disorders as a result of BFO substitution. The evolution of relaxor behavior and its microscopic mechanisms studied in this work are insightful for a better understanding the multirelaxor properties in multiferroics. Moreover, further substitution of BFO (x ≥ 0.2) flattens the permittivity curves and leads to a temperature-stable variation of high dielectric constant (≈ 103) in a wide temperature range, making the PFW-BFO solid solution attractive for such applications as high energy density capacitors.  相似文献   

13.
0.725BiFe1?xScxO3–0.275BaTiO3 + y mol% MnO2 multiferroic ceramics were fabricated by a conventional ceramic technique and the effects of Sc doping and sintering temperature on microstructure, multiferroic, and piezoelectric properties of the ceramics were studied. The ceramics can be well sintered at the wide low sintering temperature range 930°C–990°C and possess a pure perovskite structure. The ceramics with x/y = 0.01–0.02/1.0 sintered at 960°C possess high resistivity (~2 × 109 Ω·cm), strong ferroelectricity (Pr = 19.1–20.4 μm/cm2), good piezoelectric properties (d33 = 127–128 pC/N, kp = 36.6%–36.9%), and very high Curie temperature (618°C–636°C). The increase in sintering temperature improves the densification, electric insulation, ferroelectric, and piezoelectric properties of the ceramics. A small amount of Sc doping (x ≤ 0.04) and the increase in the sintering temperature significantly enhance the ferromagnetic properties of the ceramics. Improved ferromagnetism with remnant magnetization Mr of 0.059 and 0.10 emu/g and coercive field Hc of 2.51 and 2.76 kOe are obtained in the ceramics with x/y = 0.04/1.0 (sintered at 960°C) and 0.02/1.0 (sintered at 1050°C), respectively. Because of the high TC (636°C), the ceramic with x/y = 0.02/1.0 shows good temperature stability of piezoelectric properties. Our results also show that the addition of MnO2 is essential to obtain the ceramics with good electrical properties and electric insulation.  相似文献   

14.
溶胶-凝胶法制备La0.65Sr0.35MnO3及其光催化性能   总被引:4,自引:0,他引:4  
采用溶胶-凝胶法合成了以Sr取代部分稀土金属La的La0.65Sr0.35MnO3样品,经XRD衍射分析确定其具有钙钛矿的晶体结构,并对其进行了光催化活性实验.结果表明:在700℃时,La0.65Sr0.35MnO3样品平均粒径为19 nm;在太阳光照射下,LA0.65Sr0.35MnO3降解亚甲基蓝溶液120 min时,其降解率达到90%.  相似文献   

15.
Physical and chemical properties of poly(ethylene glycol) (PEG)-containing TiO2-SiO2 gel films have been studied relative to their application to the fine-patterning technique for optical memory disks. PEG added to TiO2-SiO2 gel films decomposed completely at temperatures between 250° and 300°C. The combustion of PEG in the gel films led to decreases in the refractive index and in the hardness of the films, which should result from the increase in porosity of the films. The addition of PEG into the gel films, however, did not adversely influence the weathering resistance of the glass substrates coated with the sol-gel-derived films.  相似文献   

16.
用溶胶凝胶工艺在Pt/Ti/SiO2/Si基片上沉积了Bi5FeTi3O15(BFTO)薄膜,研究了前驱液浓度和退火升温速率对BFTO薄膜结晶的影响,前驱液浓度低于0.05mol/L时不利于4层层状钙钛矿结构的形成。沉积BFTO薄膜的最佳制备工艺为:前驱液浓度为0.05mol/L和氧气氛中退火速率为4℃/s。室温下,用最佳工艺制得的BFTO薄膜显示出良好的铁电性,在300 kV/cm的外加电场下,样品的剩余极化强度2Pr达到43.4μC/cm2;同时,BFTO薄膜也显示出弱铁磁性。为了研究其磁性来源,分别在氧气氛和氮气氛下对BFTO薄膜样品进行退火,分析其磁性的差异。认为BFTO薄膜室温下的弱铁磁性主要来源于F中心交换作用。  相似文献   

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