物理学报
物理學報
물이학보
2013年
9期
421-429
,共9页
宋桂林%罗艳萍%苏健%周晓辉%常方高*
宋桂林%囉豔萍%囌健%週曉輝%常方高*
송계림%라염평%소건%주효휘%상방고*
铁磁电材料%磁滞回线%磁相变温度
鐵磁電材料%磁滯迴線%磁相變溫度
철자전재료%자체회선%자상변온도
multiferroic%magnetic hysteresis loops%leakage current
采用快速液相烧结法制备BiFeO3和Bi0.95Dy0.05Fe1-xCoxO3(x=0,0.05,0.1,0.15)陶瓷样品.实验结果表明:所有样品的主衍射峰与纯相BiFeO3相符合且具有良好的晶体结构,随着Co3+掺杂量的增大, Bi0.95Dy0.05Fe1-xCoxO3样品的主衍射峰由双峰(104)与(110)逐渐重叠为单峰(110),当掺杂量x>0.05时,样品呈现正方晶系结构;SEM形貌分析可知: Dy3+, Co3+共掺杂使BiFeO3晶粒尺度由原来的3-5μm减小到约1μm.室温下, BiFeO3样品表现出较弱的铁磁性,随着Dy3+和Co3+掺杂, BiFeO3样品的铁磁性显著提高.在外加磁场为30 kOe的作用下, Bi0.95Dy0.05Fe1-xCoxO3(x=0.05,0.1,0.15)的Mr分别为0.43,0.489,0.973 emu/g;MS分别为0.77,1.65,3.08 emu/g. BiFeO3和Bi0.95Dy0.05Fe1-xCoxO3样品磁矩M 随着温度T 的升高而逐渐减小, Dy掺杂使BiFeO3样品的TN 由644 K升高到648 K,而TC基本没有变化. Dy和Co共掺杂导致BiFeO3样品磁相变温度TC由870 K降低到780 K,其TC变化主要取决于Fe-O-Fe反铁磁超交换作用的强弱和磁结构的相对稳定性.
採用快速液相燒結法製備BiFeO3和Bi0.95Dy0.05Fe1-xCoxO3(x=0,0.05,0.1,0.15)陶瓷樣品.實驗結果錶明:所有樣品的主衍射峰與純相BiFeO3相符閤且具有良好的晶體結構,隨著Co3+摻雜量的增大, Bi0.95Dy0.05Fe1-xCoxO3樣品的主衍射峰由雙峰(104)與(110)逐漸重疊為單峰(110),噹摻雜量x>0.05時,樣品呈現正方晶繫結構;SEM形貌分析可知: Dy3+, Co3+共摻雜使BiFeO3晶粒呎度由原來的3-5μm減小到約1μm.室溫下, BiFeO3樣品錶現齣較弱的鐵磁性,隨著Dy3+和Co3+摻雜, BiFeO3樣品的鐵磁性顯著提高.在外加磁場為30 kOe的作用下, Bi0.95Dy0.05Fe1-xCoxO3(x=0.05,0.1,0.15)的Mr分彆為0.43,0.489,0.973 emu/g;MS分彆為0.77,1.65,3.08 emu/g. BiFeO3和Bi0.95Dy0.05Fe1-xCoxO3樣品磁矩M 隨著溫度T 的升高而逐漸減小, Dy摻雜使BiFeO3樣品的TN 由644 K升高到648 K,而TC基本沒有變化. Dy和Co共摻雜導緻BiFeO3樣品磁相變溫度TC由870 K降低到780 K,其TC變化主要取決于Fe-O-Fe反鐵磁超交換作用的彊弱和磁結構的相對穩定性.
채용쾌속액상소결법제비BiFeO3화Bi0.95Dy0.05Fe1-xCoxO3(x=0,0.05,0.1,0.15)도자양품.실험결과표명:소유양품적주연사봉여순상BiFeO3상부합차구유량호적정체결구,수착Co3+참잡량적증대, Bi0.95Dy0.05Fe1-xCoxO3양품적주연사봉유쌍봉(104)여(110)축점중첩위단봉(110),당참잡량x>0.05시,양품정현정방정계결구;SEM형모분석가지: Dy3+, Co3+공참잡사BiFeO3정립척도유원래적3-5μm감소도약1μm.실온하, BiFeO3양품표현출교약적철자성,수착Dy3+화Co3+참잡, BiFeO3양품적철자성현저제고.재외가자장위30 kOe적작용하, Bi0.95Dy0.05Fe1-xCoxO3(x=0.05,0.1,0.15)적Mr분별위0.43,0.489,0.973 emu/g;MS분별위0.77,1.65,3.08 emu/g. BiFeO3화Bi0.95Dy0.05Fe1-xCoxO3양품자구M 수착온도T 적승고이축점감소, Dy참잡사BiFeO3양품적TN 유644 K승고도648 K,이TC기본몰유변화. Dy화Co공참잡도치BiFeO3양품자상변온도TC유870 K강저도780 K,기TC변화주요취결우Fe-O-Fe반철자초교환작용적강약화자결구적상대은정성.
Multiferroic Bi0.95Dy0.05Fe1-xCoxO3 (x=0, 0.05, 0.1, 0.15) ceramics were prepared by rapid liquid phase sintering method. We studied the effect of (Dy+Co) doping on the structure, electrical and ferromagnetism properties of BiFeO3 ceramics. The structure and morphology of BiFeO3 ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopey (SEM). The results showed that all the peaks for Bi0.95Dy0.05Fe1-xCoxO3 samples can be indexed based on the crystal structure of pure BiFeO3. And XRD analysis revealed a phase transition in (Dy+Co) co-doped BiFeO3 when x was larger than 0.1 and grain sizes changed from 1 to 5 μm. Magnetic hysteresis loops were clearly observed in co-substituted specimens and magnetization was greatly improved. Magnetic measurements showed that all samples possess strong ferromagnetism at room temperature expect BiFeO3 and Bi0.95Dy0.05FeO3, which are weakly ferromagnetic. The M′rs, of Bi0.95Dy0.05Fe1-xCoxO3 with x=0.05, 0.01 and 0.15 are 0.43, 0.489, 0.973 emu/g and the M′rs of them are 0.77, 1.65, 3.08 emu/g, respectively. The magnetic moment of BiFeO3 and B0.95Dy0.05Fe1-xCoxO3 ceramics varies with temperature from 300 to 900 K at an applied field of 5 kOe. It shows that the TN of BiFeO3 from 644 to 648 K with different content of Dy3+can be changed by crystal structures and exchanges between Dy3+-Fe3+. The phase transition temperature of Bi0.95Dy0.05Fe1-xCoxO3 shifted to lower temperatures from 870 K to 780 K demonstrate that Co3+ doping causes a drop of TC as compared with BiFeO3. The change of TC of Bi0.95Dy0.05Fe1-xCoxO3 depends mainly on the Fe-O-Fe super-exchange strength and the relative stability of magnetic structure.
