Magnetism and Transport Properties of EuCdBi 2 with Bi Square Net.

We report a possible coexistence of nontrivial topology and antiferromagnetism in the newly discovered compounds EuCdBi 2 , with magnetic Eu layer locating above and below Bi square net. The X-ray diffraction on single crystals and powder indicats that this 112-type material crystalizes in space group of I 4 / m m m , the same as SrMnBi 2 and EuMnBi 2 . Our combined measurements of magnetization, electrical transport and specific heat consistently reveal antiferromagnetic (AFM) transition of Eu 2 + moments at T N = 20 K. The Eu moments are not saturated under a field of 7 T at 1.8 K. The anisotropic susceptibility suggests the Eu moments lie in the a b plane, and a metamagnetic (MM) transition is observed near 1 T below T N . Large positive magnetoresistance (MR) present for both H   ‖   a b and H   ‖   c , which are considered to contain part contributions from Dirac bands. Hall measurements show the electron-hole compensation effect is prominent above 100 K, with a crossover of Hall resistance from negative to positive values at ∼150 K. The fitted mobility of electrons is as high as 3250 cm 2 V − 1 S − 1 at 1.8 K. Interestingly, the rapid increase of carrier density and suppression of mobility appear at around T N , indicating non-negligible interaction between Eu moments and electron/hole bands. EuCdBi 2 may provide a new platform to investigate the interplay of topological bands and antiferromagnetic order. [ABSTRACT FROM AUTHOR]