NUCLEAR-RESONANCE AND RELAXATION IN INTERMEDIATE-VALENT YBCUAL

被引：43

作者：

MACLAUGHLIN, DE ^{[1
]}

BOER, FRD ^{[1
]}

BIJVOET, J ^{[1
]}

CHATEL, PFD ^{[1
]}

MATTENS, WCM ^{[1
]}

机构：

[1] UNIV AMSTERDAM,NATUURKUNDIG LAB,NL-1018 XE AMSTERDAM,NETHERLANDS

来源：

JOURNAL OF APPLIED PHYSICS | 1979年 / 50卷 / 03期

关键词：

D O I：

10.1063/1.327069

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

27Al NMR shifts and spin-lattice relaxation times have been measured in the intermediate-valent compound YbCuAl over the temperature range 4.2 K to 295 K. Above Tmax?25 K, the temperature for which the bulk susceptibility χ exhibits a maximum, a linear relation was observed between K and χ: K=7.5(5) ×10-4-0.19(1) χ (emu/mole). For T<Tmax this relation was no longer obeyed; at 4.2 K the shift was about 20% more positive than predicted from the linear relation and the measured χ. Satellite NMR in the Kondo alloy CuFe exhibits no such nonlinearity. It is tentatively attributed to a temperature-dependent effect of intermediate valence on the transferred hyperfine coupling between Yb moments and 27Al nuclei. Relaxation data yield a 4f spin fluctuation rate which decreases by about a factor of 2 between Tmax and 100 K. A simple ionic model for the intermediate-valent state accounts qualitatively for this observation. Further corroborating experiments are suggested.

引用

页码：2094 / 2096

页数：3

共 22 条

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