CAJ | 학술논문

采用固相烧结法制备了名义成分为La1-xKxMnO3(x＝0.1～0.4)和La0.8K0.2-yAgyMnO3(y＝0～0.2)的多晶样品,发现用K、Ag取代La后,可使菱面体结构的这种钙钛矿型稀土锰氧化物居里温度升高至室温附近,从而使样品的室温磁电阻增大,其中La0.8K0.2MnO3在μ0H＝1T磁场下的磁电阻可达13．5%.该值比单纯掺Na和掺Ag的同样成分的稀土锰氧化物的磁电阻要大.通过对磁电阻与磁化强度之间密切关系的讨论,探讨了磁电阻效应的微观机理.
채용고상소결법제비료명의성분위La1-xKxMnO3(x＝0.1～0.4)화La0.8K0.2-yAgyMnO3(y＝0～0.2)적다정양품,발현용K、Ag취대La후,가사릉면체결구적저충개태광형희토맹양화물거리온도승고지실온부근,종이사양품적실온자전조증대,기중La0.8K0.2MnO3재μ0H＝1T자장하적자전조가체13．5%.해치비단순참Na화참Ag적동양성분적희토맹양화물적자전조요대.통과대자전조여자화강도지간밀절관계적토론,탐토료자전조효응적미관궤리.
Polycrystalline samples of La1-xKxMnO3(x＝0．1～0．4) and La0．8K0．2-yAgyMnO3(y＝0～0．2) were prepared by conventional solid-state reaction processing in air． It is found that when La is substituted by K or/and Ag, the Curie temperature(TC) of the perovskite manganites with rhombohedronal structure increases up to room temperature, and the r．t． magnetoresistance(MR) increases, of which the r．t． MR of the sample with a composition of La0．8K0．2MnO3 is up to 13．5% at μ0H＝1T, which is higher than that of the manganites only doping Na and Ag with same concentration． In addition, our results show that there is a close relationship between MR and magnetization． The microscopic mechanism of MR effect is discussed in this paper．