摘要
研究了溶胶 -凝胶法制备氧化物巨磁电阻材料的工艺 ,制备了La0 .7Sr0 .3 CrxMn1-xO3 (x =0 ,0 .10 ,0 .15 )和La0 .7Sr0 .3 FexMn1-xO3 (x =0 .0 5 ,0 .10 ,0 .16 )两系列的单相钙钛矿锰氧化物多晶样品 ,并研究了Cr ,Fe替代La0 .7Sr0 .3 MnO3 中部分Mn后对其结构、磁性和巨磁电阻性质的影响 .观察到La0 .7Sr0 .3 Cr0 .15Mn0 .85O3 和La0 .7Sr0 .3 Fe0 .0 5Mn0 .95O3 两个样品的电阻 温度曲线都出现了双峰 .定性讨论了可能产生双峰的机制 .随Cr(或Fe)替代量的增加 ,材料的居里温度很快下降 ,铁磁性减弱 ,导电性降低 ,巨磁电阻效应增强 .但与Fe掺杂相比 ,相同数量的Cr掺杂对材料的影响要小 .
This paper discusses the preparation of the colossal magnetoresistance samples La 0.7 Sr 0.3 Cr x Mn 1- x O 3 ( x =0, 0.10, 0.15) and La 0.7 Sr 0.3 Fe x Mn 1- x O 3 ( x =0.05,0.10,0.16) by the sol gel technique. The effects that the substitution of Cr or Fe for Mn in La 0.7 Sr 0.3 MnO 3 affects its structure, magnetic properties and magnetoresistance are also studied. Two peaks are observed on the resistance\|temperature curves ( R\|T curves) of the two samples La 0.7 Sr 0.3 Cr 0.15 Mn 0.85 O 3 and La 0.7 Sr 0.3 Fe 0.05 Mn 0.95 O 3. The mechanism for the potential appearance of the double peaks is discussed. A conclusion is drawn that with the increase of Cr (or Fe) substituting for Mn, the samples' Curie temperature ( T C), ferromagnetism and conductivity decrease, whereas their magnetoresistance strengthens. However, the same amount of Cr produces less effect on the samples than the same amount of Fe.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第7期1366-1370,共5页
Acta Physica Sinica
基金
国家自然科学基金! (批准号 :5 95 2 5 10 1)
关键词
巨磁电阻效应
钙钛矿锰氧化物
磁性
CMR effect, sol\|gel technology, R\|T curve, metal\|insulator transition
