Magnetostriction measurements for the Ising-type itinerant metamagnetic compound UCoAl were performed under uniaxial stress for σ || c-axis using an in situ pressure-tuning device. A ferromagnetic transition was clearly observed at zero magnetic field at least above ∼0.05 GPa. For a stress of 0.1 GPa, the FM transition is of 2nd order, since the anomaly of the thermal expansion coefficient does not show any hysteresis at the transition. No step like behavior was observed for the FM transition under uniaxial stress in the present study. From the precise stress dependence of TC, a change of the power (n) law from 3/4 to 1/2 was also found at around 0.1 GPa for the expression of TC(σ) ∝ (σ − σc)n, where the critical value is σc ∼ 0.026 GPa.
Journal of the Physical Society of Japan Vol .84, 023704 (2015).