Pressure evolution of the metamagnetic transition in UCoAl As measured using ⁵⁹ Co NMR

We have performed NMR measurements under pressure in UCoAl with a quantum critical endpoint of the metamagnetic transition from the paramagnetic phase to the ferromagnetic (FM) phase. ⁵⁹ Co-NMR sensitively detects the evolution of the internal field caused by applying the external field. The metamagnetic field H _m increases with increasing pressure consistently with other experimental methods, accompanied by the suppression of the magnetization in the field-induced FM phase and the magnetization jump at H _m . The loss of the NMR signal on approaching the QCEP indicates the development of the spin fluctuations.