Field-induced magnetic transitions in the quasi-two-dimensional heavy-fermion antiferromagnets Ce{sub n}RhIn{sub 3n+2} (n=1 or 2)
Field-induced magnetic transitions in the quasi-two-dimensional heavy-fermion antiferromagnets Ce{sub n}RhIn{sub 3n+2} (n=1 or 2)
复制标题
准二维重费米子反铁磁体 Ce{sub n}RhIn{sub 3n 2} (n=1 或 2) 中的场感应磁转变
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Sarrao
中科院分区：
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作者：
Andrew Cornelius;P. G. Pagliuso;M. Hundley;J. Sarrao
我们测量了四方反铁磁体 CeRhIn{sub 5} 和 Ce{sub 2}RhIn{sub 8} 的场相关热容，两者的电子比热系数 {gamma}{approx}400 mJ/mol Ce K{sup 2} 均高于 T{sub N}。对于 T<T{sub N}，零外加磁场下的比热数据与 CeRhIn{sub 5} 费米表面中打开间隙的各向异性自旋密度波的存在一致，而 Ce{sub 2}RhIn{sub 8} 表现出与简单反铁磁磁振子一致的行为。从这些结果来看，与晶体结构类似，CeRhIn{sub 5} 中的磁结构比 Ce{sub 2}RhIn{sub 8} 中的二维性更强，其中只有约 12% 的费米表面保持无间隙，而 Ce{sub 2}RhIn{sub 8} 的费米表面为 92%。当 B||c 时，两种化合物都以重费米系统预期的方式表现，因为 T{sub N} 和电子热容都随着施加场而减小。当在四方基面 (B||a) 上施加场时，CeRhIn{sub 5} 和 Ce{sub 2}RhIn{sub 8} 具有非常相似的相图，其中包含一阶和二阶场感应磁转变。
We have measured the field-dependent heat capacity in the tetragonal antiferromagnets CeRhIn{sub 5} and Ce{sub 2}RhIn{sub 8}, both of which have an enhanced value of the electronic specific heat coefficient {gamma}{approx}400 mJ/mol Ce K{sup 2} above T{sub N}. For T<T{sub N}, the specific heat data at zero applied magnetic field are consistent with the existence of an anisotropic spin-density wave opening a gap in the Fermi surface for CeRhIn{sub 5}, while Ce{sub 2}RhIn{sub 8} shows behavior consistent with a simple antiferromagnetic magnon. From these results, the magnetic structure, in a manner similar to the crystal structure, appears more two dimensional in CeRhIn{sub 5} than in Ce{sub 2}RhIn{sub 8} where only about 12% of the Fermi surface remains ungapped relative to 92% for Ce{sub 2}RhIn{sub 8}. When B||c, both compounds behave in a manner expected for heavy-fermion systems as both T{sub N} and the electronic heat capacity decrease as field is applied. When the field is applied in the tetragonal basal plane (B||a), CeRhIn{sub 5} and Ce{sub 2}RhIn{sub 8} have very similar phase diagrams which contain both first- and second-order field-induced magnetic transitions.