| (La0.67Ca0.33MnO3)x/(ZrO2)1-x复合体系的磁性和传输特性 |
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| 引用本文： | 黄宝歆,刘宜华,张汝贞,原晓波,王成建,郝小鹏.(La0.67Ca0.33MnO3)x/(ZrO2)1-x复合体系的磁性和传输特性[J].中国稀土学报,2004,22(6):755-759. |
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| 作者姓名： | 黄宝歆 刘宜华 张汝贞 原晓波 王成建 郝小鹏 |
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| 作者单位： | 1. 山东大学物理学院和晶体材料国家重点实验室,山东,济南,250100;潍坊学院物理系,山东潍坊,261043
2. 山东大学物理学院和晶体材料国家重点实验室,山东,济南,250100 |
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| 基金项目： | 国家重点基础研究发展计划(973计划) |
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| 摘 要： | 将用溶胶-凝胶法得到的La0.67Ca0.33MnO3(LCMO)微粉与ZrO2的颗粒进行复合,制备了(LCMO)x/(ZrO2)1-x渗流复合体系.当LCMO的体积分数为40%时,复合体系达到渗流阈值,此时材料在低温下的磁电阻得到显著增强.77 K时在10 mT的磁场下,(LCMO)0.4/(ZrO2)0.6的磁电阻比为7.8%,相对于LCMO增加了712%.低场磁电阻(LFMR)的增强是由于载流子在二者界面处发生的自旋相关隧穿效应.由于界面反应,不可避免地产生了Zr离子对Mn离子的B位替代,从而引起材料磁性M和居里温度Tc的下降.在x＜60%时,Tc保持在220 K附近基本不变,说明该B位替代是有限的.
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| 关 键 词： | 无机非金属材料 复合体系 庞磁电阻 界面隧穿 低场磁电阻 稀土 |
| 文章编号： | 1000-4343(2004)06-0755-05 |
Magnetic and Magnetoresistance Properties in (La0.67Ca0.33MnO3)x/(ZrO2)1-x Composite System |
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| Huang Baoxin.Magnetic and Magnetoresistance Properties in (La0.67Ca0.33MnO3)x/(ZrO2)1-x Composite System[J].Journal of the Chinese Rare Earth Society,2004,22(6):755-759. |
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| Authors: | Huang Baoxin |
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| Institution: | Huang Baoxin~ |
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| Abstract: | The (La_(0.67)Ca_(0.33)MnO_3)_x/(ZrO_2)_(1-x) (x is the volume fraction ratio) percolated composites were fabricated by combining La_(0.67)Ca_(0.33)MnO_3 (LCMO) powders with ZrO_2 particles, where the LCMO powders were prepared by sol-gel process. The low field magnetoresistance (LFMR) is greatly enhanced at low temperature when the system is close to the metallic percolation threshold of x=0.4. The magnetoresistance ratio of (LCMO)_(0.4)/(ZrO_2)_(0.6) in a 10 mT magnetic field at 77 K is 7.8%, about by 712% larger than that of the pure LCMO compound. The enhancement of the spin-dependent tunneling of the electrons at the interfaces of LCMO and ZrO_2 grains is responsible for the enhanced LFMR. With increasing ZrO_2 addition, the Curie temperature T_C decreases firstly and then remains a constant at about 220 K when x<60%, showing the limited substitution effect of Zr ions on the B sites. |
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| Keywords: | inorganics non-metallic materials composite system colossal magnetoresistance interfacial tunneling low-field magnetoresistance rare earths |
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