In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the Co59 nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co1-xFex)Al(x=0,0.5,1,and2%) in zero external magnetic field. The Fe concentration dependence of Co59-NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above x=1%. The magnetic fluctuations along the c axis detected by the nuclear spin-spin relaxation rate 1/T2 exhibit an anomaly at Tmax∼20K and enhance with increasing x. These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2015 Feb 26|