Uniaxial magnetic anisotropy and anomalous Hall effect in the ferromagnetic compound PrMn2Ge2

Noncolinear or noncoplanar spin configurations in magnetic materials usually give rise to a fascinating array of physical phenomena. Here, we perform a systematic study of magnetic and electronic transport properties in a noncolinear itinerant magnet ${\mathrm{PrMn}}_{2}{\mathrm{Ge}}_{2}$. With the field applied along different directions, ${\mathrm{PrMn}}_{2}{\mathrm{Ge}}_{2}$ displays uniaxial magnetic anisotropy with an easy axis along the $c$ axis. Both the temperature-dependent magnetization and longitudinal resistivity reveal an anomaly at 330 K, well corresponding to the magnetic transition of the Mn sublattice from a colinear antiferromagnetic state to a canted ferromagnetic state. Strikingly, ${\mathrm{PrMn}}_{2}{\mathrm{Ge}}_{2}$ exhibits anomalous Hall effect (AHE) together with prominent negative magnetoresistivity (MR) when the field is applied along the $c$ axis. The negative MR can be linked to the suppression of spin scattering. Based on the scaling analysis between the anomalous Hall resistivity ${\ensuremath{\rho}}_{yx}^{A}$ and longitudinal resistivity ${\ensuremath{\rho}}_{xx}$, the relationship ${\ensuremath{\rho}}_{yx}^{A}\ensuremath{\propto}{\ensuremath{\rho}}_{xx}^{1.18}$ has been given, which indicates that the observed AHE in ${\mathrm{PrMn}}_{2}{\mathrm{Ge}}_{2}$ is likely dominated by the skew-scattering mechanism. Simultaneously, a sharp jump has been observed in the hysteresis loop, which is also discernible in the field dependence of Hall resistivity and magnetoresistivity. Such features presumably result from the movement of the domain wall.