Quantum criticality in Nd Fe 2 Ga 8 under magnetic field

We studied the magnetism in ${\mathrm{NdFe}}_{2}{\mathrm{Ga}}_{8}$ by magnetic susceptibility, specific heat, and resistivity measurements, which show ${\mathrm{Nd}}^{3+}$ ions forming one-dimensional chains along the $c$ axis. At zero field, two magnetic transitions are found at about 15 and 11 K. For field vertical to the $c$ axis, no significant effects on the magnetic orders are found. On the other hand, the two transitions are merged together at about 4 T for field parallel to the $c$ axis and completely suppressed at about 7 T. The suppression of the magnetic order results in quantum critical behaviors of the conventional three-dimensional spin-density-wave type, such as $\ensuremath{\rho}\ensuremath{\sim}{T}^{1.5}$ and $C/T\ensuremath{\sim}{T}^{\ensuremath{-}0.5}$. However, the temperature dependence of the resistivity is replaced by a ${T}^{0.5}$ behavior at very low temperatures for field larger than 3 T, which is attributed to the field-induced ferromagnetic moment. Our results suggest that there may be couplings between the antiferromagnetic quantum critical fluctuations and the field-induced ferromagnetic fluctuations.