Quasi-one-dimensional spin dynamics in d-electron heavy-fermion metal Y_1-xSc_xMn₂

Slow spin fluctuations (v10¹² s^-1) observed by the muon spin relaxation technique in Y^i-xSc^xMn² exhibits a power law dependence on temperature (v ∝ T^α ), where the power converges asymptotically to unity (α → 1) as the system moves away from spin-glass instability with increasing Sc content x. This linear T dependence, which is common to that observed in LiV₂O ₄, is in line with the prediction of the 'intersecting Hubbard chains'' model for a metallic pyrochlore lattice, suggesting that the geometrical constraints to t_2g bands specific to the pyrochlore structure serve as a basis of the d-electron heavy-fermion state.