Cascade of Magnetic Phase Transitions and Large Topological Hall Effect in the Non-centrosymmetric Antiferromagnet Eu2Pd3Bi4

The interplay between symmetry-breaking, spin-orbit coupling, and magnetic frustration in non?centrosymmetric antiferromagnets has emerged as a fertile ground for discovering intertwined topo?logical and quantum phenomena. Here we report a cascade of magnetic phase transitions and a large topological Hall response in the newly-discovered non-centrosymmetric antiferromagnetic (AFM) material Eu2Pd3Bi4 with a Neel temperature TN = 7.6 K. Under magnetic fields (H) parallel to the c-axis, two successive phase transitions at critical fields H1 and H2 are observed in magnetization at temperatures below TN , which are attributed to the occurrences of sequential field-induced spin states. A pronounced topological Hall effect signal emerges exclusively within an intermediate field window H1 H H2, signifying the formation of topological spin textures. The field-temperature phase diagram mapped via specific heat and magnetoelectric transport measurements incorporates five phase regimes: the paramagnetic state, a high-field polarized state and three AFM states with distinct spin configurations. Our results identify Eu2Pd3Bi4 as a good candidate for scrutinizing sophisticated interplays between magnetic structure and nontrivial band topology