Field-tuned Fermi liquid in quantum critical YFe₂Al₁₀

We present measurements of the magnetization M, ac susceptibility χ^′, electrical resistivity ρ, and specific heat C in single crystals of metallic YFe₂Al₁₀. The magnetic susceptibility follows a Curie-Weiss temperature dependence for 75K≤T≤750 K, with a fluctuating Fe moment of 0.45μ_B/Fe, and the ac susceptibility χ^′ diverges at lower temperatures χ^′∼T^-1.28^±0.04 when the ac field is in the basal plane. The field B and temperature T dependencies of the magnetization M are well described by the scaling expression MT ^-β = F(B/Tβ⁺γ) for 1.8K≤T≤30 K and for fields larger than 0.1T. These results indicate that strong quasi-two-dimensional critical fluctuations are present that can be suppressed by magnetic fields. The magnetic and electronic parts of the specific heat C_M show a similar divergence for 0.4K≤T≤12 K, where C _M/T∼T^-0.47^±0.03. The divergences in χ^′ and C_M/T indicate that YFe₂Al ₁₀ is located near a quantum critical point, and no magnetic order is observed above 0.09 K. We argue that our results are inconsistent with quantum impurity or disorder models, suggesting instead that YFe₂Al ₁₀ is on the verge of bulk magnetic ordering, and that the critical fluctuations that are associated with this quantum critical point lead to the divergencies in C_M/T and χ^′.