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 <i>T</i>_N = 7.6 K. Under magnetic fields (<i>H</i>) parallel to the c-axis, two successive phase transitions at critical fields<i> H</i>₁ and <i>H</i>₂ are observed in magnetization at temperatures below <i>T</i>_N , 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 <i>H</i>₁ &lt; <i>H</i> &lt; <i>H</i>₂, 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