Large positive magnetoresistance and anisotropic magnetoresistance in a layered antiferromagnetic EuAl2Ge2

Abstract

Magnetoresistance (MR) and anisotropic magnetoresistance (AMR) are fundamental probes of charge transport in magnetic materials. In most magnetic systems, the MR is relatively small due to strong spin-dependent scattering, rendering large positive MR rare. Here, we report the successful growth of high-quality single crystals of the antiferromagnetic compound EuAl2Ge2 and the observation of an extremely large positive MR of up to 2542%, accompanied by a giant AMR reaching 1427%. Comprehensive transport measurements reveal that the pronounced MR and AMR arise from the high crystalline quality, electron–hole compensation, and the strong anisotropy of the Fermi surfaces. These results demonstrate that a layered crystal structure featuring spatially separated magnetic and conducting layers provides an effective route to achieving large magnetotransport responses in magnetic materials.