Magnetism and Transport Properties of EuCdBi2 with Bi Square Net

We report a possible coexistence of nontrivial topology and antiferromagnetism in the newly discovered compounds EuCdBi2, 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 I4/mmm, the same as SrMnBi2 and EuMnBi2. Our combined measurements of magnetization, electrical transport and specific heat consistently reveal antiferromagnetic (AFM) transition of Eu2+ 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 ab plane, and a metamagnetic (MM) transition is observed near 1 T below T-N. Large positive magnetoresistance (MR) present for both H parallel to ab and H parallel to 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 similar to 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. EuCdBi2 may provide a new platform to investigate the interplay of topological bands and antiferromagnetic order.

Automated summary

We report the possible coexistence of nontrivial topology and antiferromagnetism in EuCdBi2. X-ray diffraction results show that EuCdBi2 has the same space group as SrMnBi2 and EuMnBi2. Magnetization, electrical transport, and specific heat measurements indicate an antiferromagnetic transition at 20 K. The large positive magnetoresistance is considered to come from Dirac bands, and Hall measurements show a crossover of Hall resistance from negative to positive values at around 150 K. EuCdBi2 could serve as a new platform to study the interplay of topological bands and antiferromagnetic order.