Weak quasistatic magnetism in the frustrated Kondo lattice Pr2Ir2O7
Weak quasistatic magnetism in the frustrated Kondo lattice Pr2Ir2O7
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DOI：
10.1016/j.physb.2008.11.167
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发表时间：
2009-04-15
影响因子：
2.8
通讯作者：
Bernal, O. O.
中科院分区：
文献类型：
--
作者：
MacLaughlin, D. E.;Ohta, Y.;Bernal, O. O.
在0.025 ~ 250 K的温度范围内，在铱酸盐Pr2Ir2O7中进行了介子自旋弛豫实验。Kubo-Toyabe松弛函数被观察到大于或类似于200k，表明在这个温度范围内的静态磁性。T ->静态μ子自旋弛豫率δ(0)近似于8 μ s(-1)，意味着弱准静态矩（类似于0.1 μ (B)）。A的温度依赖性是高度非平均场的，平滑地以数量级递减，但在T < T-f时保持非零。该数据排除了将Pr3+ CEF的完整基态力矩（3.0 mu(B)）排序到0.025 K的可能性。弱静磁性很可能是由超细增强的Pr-141核磁引起的。在接近20 K以下，动态弛豫率A显著增加，这可能是由于自旋-液态的自旋涨落减缓所致。在低温下，λ是强的且与温度无关，表明在受挫的反铁磁体中存在高密度的低洼自旋激发。(C) 2008 Elsevier B.V.版权所有
Muon spin relaxation experiments have been performed in the pyrochlore iridate Pr2Ir2O7 for temperatures in the range 0.025-250 K. Kubo-Toyabe relaxation functions are observed up to greater than or similar to 200 K, indicating static magnetism over this temperature range. The T -> 0 static muon spin relaxation rate Delta(0) approximate to 8 mu s(-1) implies a weak quasistatic moment (similar to 0.1 mu(B)). The temperature dependence of A is highly nonmean-field-like, decreasing smoothly by orders of magnitude but remaining nonzero for T < T-f. The data rule out ordering of the full Pr3+ CEF ground-state moment (3.0 mu(B)) down to 0.025 K. The weak static magnetism is most likely due to hyperfine-enhanced Pr-141 nuclear magnetism. The dynamic relaxation rate A increases markedly below similar to 20 K probably due to slowing down of spin fluctuations in the spin-liquid state. At low temperatures lambda is strong and temperature-independent, indicative of a high density of low-lying spin excitations as is common in frustrated antiferromagnets. (C) 2008 Elsevier B.V. All rights reserved.