Topological Hall effect driven by short-range magnetic order in EuZn2As2

Short-range (SR) magnetic orders such as magnetic glass orders or fluctuations in a quantum system usually host exotic states or critical behaviors. Like the long-range (LR) magnetic orders, SR magnetic orders can also break time-reversal symmetry and drive the nonzero Berry curvature leading to novel transport properties. In this work, we report that in EuZn2As2 compound, besides the LR A-type antiferromagnetic (AF) order, the SR magnetic order is observed in a wide temperature region. Magnetization measurements and electron spin resonance (ESR) measurements reveal the ferromagnetic (FM) correlations for this SR magnetic order which results in an obvious anomalous Hall effect above the AF transition. Moreover the ESR results reveal that this FM SR order coexists with LR AF order exhibiting anisotropic magnetic correlations below the AF transition. The interactions of LR and SR magnetism evolving with temperature and field can host nonzero spin chirality and berry curvature leading to additional topological Hall contribution even in a centrosymmetric simple AF system. Our results indicate that EuZn2As2 is a fertile platform to investigate exotic magnetic and electronic states.