Max-Planck-Institute for Chemical Physics of Solids, D-01187 Dresden, Germany.
Phys Rev Lett. 2012 Nov 21;109(21):216402. doi: 10.1103/PhysRevLett.109.216402. Epub 2012 Nov 20.
Cerium 4f electronic spin dynamics in single crystals of the heavy-fermion system CeFePO is studied by means of ac susceptibility, specific heat, and muon-spin relaxation (μSR). Short-range static magnetism occurs below the freezing temperature T(g) ≈ 0.7 K, which prevents the system from accessing a putative ferromagnetic quantum critical point. In the μSR, the sample-averaged muon asymmetry function is dominated by strongly inhomogeneous spin fluctuations below 10 K and exhibits a characteristic time-field scaling relation expected from glassy spin dynamics, strongly evidencing cooperative and critical spin fluctuations. The overall behavior can be ascribed neither to canonical spin glasses nor other disorder-driven mechanisms.
采用交流磁化率、比热和μ子自旋弛豫（μSR）研究了重费米子体系 CeFePO 单晶体中铈的 4f 电子自旋动力学。在冻结温度 T(g) ≈ 0.7 K 以下出现短程静态磁有序，这阻止了系统进入假设的铁磁量子临界点。在 μSR 中，在低于 10 K 时，样品平均μ子不对称函数主要由强烈的非均匀自旋涨落主导，并表现出从玻璃态自旋动力学预期的特征时-场标度关系，强烈表明协同和临界自旋涨落的存在。整体行为既不能归因于典型的自旋玻璃，也不能归因于其他由无序驱动的机制。
