Pressure effects in the itinerant antiferromagnetic metal TiAu

Abstract

We report the pressure dependence of the N\'eel temperature ${T}_{N}$ up to $P\ensuremath{\approx}27$ GPa for the recently discovered itinerant antiferromagnet (IAFM) TiAu. The ${T}_{N}(P)$ phase boundary exhibits unconventional behavior in which the N\'eel temperature is enhanced from ${T}_{N}\ensuremath{\approx}33$ K at ambient pressure to a maximum of ${T}_{N}\ensuremath{\approx}35$ K occurring at $P\ensuremath{\approx}5.5$ GPa. Upon a further increase in pressure, ${T}_{N}$ is monotonically suppressed to $\ensuremath{\sim}22$ K at $P\ensuremath{\approx}27$ GPa. We also find a crossover in the temperature dependence of the electrical resistivity $\ensuremath{\rho}$ in the antiferromagnetic (AFM) phase that is coincident with the peak in ${T}_{N}(P)$, such that the temperature dependence of $\ensuremath{\rho}={\ensuremath{\rho}}_{0}+{A}_{n}{T}^{n}$ changes from $n\ensuremath{\approx}3$ during the enhancement of ${T}_{N}$ to $n\ensuremath{\approx}2$ during the suppression of ${T}_{N}$. Based on an extrapolation of the ${T}_{N}(P)$ data to a possible pressure-induced quantum critical point, we estimate the critical pressure to be ${P}_{c}\ensuremath{\approx}45$ GPa.