Comment on “Spin-cluster effect and lattice-deformation-induced Kondo effect, spin-glass freezing, and strong phonon scattering in La0.7Ca0.3Mn1−xCrxO3” [J. Appl. Phys. 97, 103908 (2005)]
Comment on “Spin-cluster effect and lattice-deformation-induced Kondo effect, spin-glass freezing, and strong phonon scattering in La0.7Ca0.3Mn1−xCrxO3” [J. Appl. Phys. 97, 103908 (2005)]
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DOI：
10.1063/1.2432355
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发表时间：
2007-02
影响因子：
3.2
通讯作者：
E. Rozenberg
中科院分区：
文献类型：
--
作者：
E. Rozenberg
在最近的一篇论文中，Wu 等人。 [J。应用。物理。 97, 103908 (2005)]报道了多晶La0.7Ca0.3Mn1−xCrxO3 (x=0.05和0.1)亚锰矿中电阻率(ρ)与温度(T)依赖性的特征。特别是，在 ρ(T) 曲线中观察到 T<50K 处的浅最小值和共存的两个最大值。吴等人。声称这些特征的出现是由于单杂质近藤效应及其与鲁德曼-基特尔-卡苏亚-吉田相互作用的竞争。在这篇评论中，表明这种解释是非常值得怀疑的，并且 ρ(T) 曲线上的低温最小值和分裂最大值这两者出现的一个更简单的原因是众所周知的晶界效应。
In a recent paper Wu et al. [J. Appl. Phys. 97, 103908 (2005)] reported on characteristic features of the temperature (T) dependence of electrical resistivity (ρ) in polycrystalline La0.7Ca0.3Mn1−xCrxO3 (x=0.05 and 0.1) manganites. In particular, a shallow minimum at T<50K and coexisting two maxima were observed in ρ(T) curves. Wu et al. claimed that these features appear due to the single-impurity Kondo effect and its competition with the Ruderman-Kittel-Kasuya-Yosida interaction. In this Comment it is shown that such interpretation is very questionable and that a much simpler reason for the appearance of both, the low temperature minimum and splitted maximum on ρ(T) curve, is the well known grain boundary effects.