Magnetic properties of the 5<b><i>f</i></b>itinerant electron metamagnet UCoAl under high pressure

Abstract

The magnetization and susceptibility of single-crystalline UCoAl were measured under high pressures to P=1.2 GPa. A sharp metamagnetic transition was observed only in magnetic fields along the c axis. The critical field is ${B}_{c}$=0.65 T at P=0 GPa, which increases with pressure and temperature. The susceptibility for ambient pressure shows a broad maximum at ${T}_{\mathrm{max}}$=20 K. The value of ${T}_{\mathrm{max}}$ increases with pressure. A theory of the itinerant metamagnetic transition has been generalized for the case of anisotropic spin fluctuations. The observed pressure dependence of the inverse susceptibility at ${T}_{\mathrm{max}},$ the temperature ${T}_{0}$ for the disappearance of the metamagnetic transition, and the temperature dependence of ${B}_{c}$ can be explained with this theory.