Large unconventional anomalous Hall effect arising from spin chirality within domain walls of an antiferromagnet EuZn2Sb2

The unconventional anomalous Hall effect was observed in the antiferromagnetic state of ${\mathrm{EuZn}}_{2}{\mathrm{Sb}}_{2}$. Scaling of unconventional Hall conductivity with the longitudinal conductivity, and the magnitude of the Hall angle indicate spin chirality despite a collinear magnetic structure. Anomalies in magnetoresistance culminate in the same fields, in which the unconventional anomalous Hall resistance has maxima. The monotonous decrease of their magnitude with increasing temperature belittles the role of spin fluctuations here, which are important in isostructural compounds. These observations point to a prominent role of scalar spin chirality within domain walls, when the magnetic field tilts the Eu moments. Simple calculation of such spin chirality shows it is strongest in fields that are characteristic for anomalous magnetotransport.