Valence and magnetic ordering in intermediate valence compounds: TmSe versus SmB6
Valence and magnetic ordering in intermediate valence compounds: TmSe versus SmB6
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DOI：
10.1088/0953-8984/18/6/021
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发表时间：
2005-11
期刊：
影响因子：
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通讯作者：
J. Derr;G. Knebel;G. Lapertot;B. Salce;M. Measson;J. Flouquet
中科院分区：
文献类型：
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作者：
J. Derr;G. Knebel;G. Lapertot;B. Salce;M. Measson;J. Flouquet
用交流微量热法研究了TmSe和SmB_6在16和18GPa压力下的低温原位压力调谐。对于TmSe（在p3 GPa下从反铁磁绝缘体转变），发现TN随p线性增加。对于准三价化合物TmS，观察到TN的类似线性p增加，其在环境压力下相当于p 7 GPa下的TmSe。在SmB 6的情况下，已经在p = 8GPa以上检测到长程磁性，即在比绝缘体到金属过渡的压力稍高的压力下。然而，均匀的磁相仅在10 GPa以上出现。的磁性和电子性质有关的重整化的4f波函数的二价或三价配置。正如在SmS中所观察到的，SmB 6中的长程磁性已经发生在远低于三价Sm 3+状态的压力下。通过假设取决于价态配置的近藤晶格温度公式，似乎可以粗略地描述中间价态平衡的物理性质。并与铈和镱重费米子化合物的长程磁性作了比较。
The intermediate valence systems TmSe and SmB6 have been investigated up to 16 and 18 GPa by ac microcalorimetry with a pressure (p) tuning realized in situ at low temperature. For TmSe, the transition from an antiferromagnetic insulator for p3 GPa), TN is found to increase linearly with p. A similar linear p increase of TN is observed for the quasitrivalent compound TmS, which is at ambient pressure equivalent to TmSe at p∼7 GPa. In the case of SmB6 long range magnetism has been detected above p∼8 GPa, i.e. at a pressure slightly higher than the pressure of the insulator to metal transition. However a homogeneous magnetic phase occurs only above 10 GPa. The magnetic and electronic properties are related to the renormalization of the 4f wavefunction either to the divalent or the trivalent configurations. As observed in SmS, long range magnetism in SmB6 occurs already far below the pressure where a trivalent Sm3+ state will be reached. It seems possible to describe roughly the physical properties of the intermediate valence equilibrium by assuming formulae for the Kondo lattice temperature depending on the valence configuration. Comparison is also made with the appearance of long range magnetism in cerium and ytterbium heavy fermion compounds.