Magnetic Phase Diagram of Triangular Lattice Eu-Based Compound EuAg4Sb2

We conducted a thorough study on the evolution of magnetic properties in the layered triangular lattice Eu-based antimonide EuAg4Sb2. The magnetic susceptibility measurements suggest that the title compound experiences two sequential anti-ferromagnetic transitions at approximately 10.8 K and 7.5 K, respectively, which is in contrast to the dominant ferromagnetic interactions indicated by a positive Curie-Weiss temperature in the paramagnetic region. This suggests the presence of a complex interaction between ferromagnetic and antiferromagnetic exchanges in EuAg4Sb2. The magnetic phase diagrams, constructed based on both magnetic susceptibility and isothermal magnetization measurements, provide unequivocal definitions for the various magnetic states observed in EuAg4Sb2. Remarkably, an intermediate transition state, accompanied by a 1/3 magnetization-plateau-like anomaly, emerges under in-plane magnetic fields, but missing under out-of-plane magnetic fields. Our result demonstrates that EuAg4Sb2 hosts intriguing magnetic properties and could be a promising platform for exploring exotic magnetic properties of Eu2+ triangular lattice compounds.