Magnetic and transport properties of the pseudobinary systems Ce(Fe1-xCox)2 and (Ce1-yScy)Fe2
Magnetic and transport properties of the pseudobinary systems Ce(Fe1-xCox)2 and (Ce1-yScy)Fe2
复制标题
伪二元系 Ce(Fe1-xCox)2 和 (Ce1-yScy)Fe2 的磁性和输运特性
DOI：
10.1103/physrevb.63.054405
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发表时间：
2001
影响因子：
3.7
通讯作者：
T. Fujita
中科院分区：
文献类型：
--
作者：
H. Fukuda;H. Fujii;H. Kamura;Y. Hasegawa;T. Ekino;N. Kikugawa;Takashi Suzuki;T. Fujita
研究了C15立方Laves相结构的非稳定铁磁体CeFe 2的磁性和输运性质的稀释替代效应。在x<0.10的Co替代体系Ce（Fe 12 xCox）2中，居里温度TC随Co含量的增加而降低，当x ≥ 0.05时，在低温区出现反铁磁有序，铁磁态到反铁磁态的转变温度T0随Co含量的增加而单调增加.而在y<0.10的Sc替代体系（Ce_（12）y Scy）Fe_2中，随着Sc含量的增加，居里温度TC和4.2K下的饱和磁化强度MS均逐渐增大。尽管在这两个系统中的替代后的晶格参数的减少，反铁磁基态稳定在Ce（Fe 12 xCox）2，而铁磁基态稳定在（Ce 12 yScy）Fe 2。这些结果表明，CeFe 2中Fe 3d - Fe 3d铁磁交换作用和由Ce 4f- Fe 3d杂化引起的反铁磁自旋关联相互竞争，4f-3d杂化效应的增强/减弱可能使CeFe 2铁磁基态不稳定/稳定.此外，Ce（Fe 12 xCox）2在4.2 K下表现出负巨磁电阻，达到约Dr/r5;60- 65%，这伴随着从反铁磁到铁磁状态的变磁转变。巨磁电阻效应起源于变磁相变后超带隙的崩塌导致费米面的重构。
We studied the dilute substitution effect on magnetic and transport properties in an unstable ferromagnet CeFe2 with a C15 cubic Laves-phase structure. In the Co substitution system Ce(Fe12xCox)2 with x<0.10, while the Curie temperature TC decreases with increasing the Co concentration, an antiferromagnetic ordering appears in the low temperature region for x^0.05, and the transition temperature T0 from ferromagnetic to antiferromagnetic states monotonously increases with increasing the Co concentration. On the other hand, in the Sc substitution system (Ce12yScy)Fe2 with y<0.10, both the Curie temperature TC and saturation magnetization M S at 4.2 K gradually increase with increasing the Sc concentration. Despite the decrease in lattice parameter upon substitution in both the systems, an antiferromagnetic ground state is stabilized in Ce(Fe12xCox)2 , whereas a ferromagnetic ground state is stabilized in (Ce12yScy)Fe2. These results indicate that the Fe 3d – Fe 3d ferromagnetic exchange interaction and the antiferromagnetic spin correlation arising from the Ce 4 f – Fe 3d hybridization compete in CeFe2, and the enhancement/depression of the 4 f -3d hybridization effect might make the ferromagnetic ground state in CeFe2 unstable/stable. Furthermore, Ce(Fe12xCox)2 exhibited a negative giant magnetoresistance reaching about Dr/r5;60– 65 % at 4.2 K, which is accompanied by a metamagnetic transition from antiferromagnetic to ferromagnetic states. The giant magnetoresistance effect is originated from the reconstruction of Fermi surface due to the collapse of the superzone gap after the metamagnetic transition.