Field-tuned critical fluctuations in YFe₂Al₁₀: Evidence from magnetization, 27Al NMR, and NQR investigations

We report magnetization, specific heat, and NMR investigations on YFe ₂Al₁₀ over a wide range of temperature and magnetic field and zero field (NQR) measurements. Magnetic susceptibility, specific heat, and spin-lattice relaxation rate divided by T(1/T₁T) follow a weak power law (∼T^-0.4) temperature dependence, which is a signature of the critical fluctuations of Fe moments. The value of the Sommerfeld-Wilson ratio and the linear relation between 1/T₁T and χ suggest the existence of ferromagnetic correlations in this system. No magnetic ordering down to 50 mK in C_p(T)/T and the unusual T and H scaling of the bulk and NMR data are associated with a magnetic instability which drives the system to quantum criticality. The magnetic properties of the system are tuned by field wherein ferromagnetic fluctuations are suppressed and a crossover from quantum critical to Fermi-liquid behavior is observed with increasing magnetic field.