Multiple Magnetic Phase Transitions and Critical Behavior in Single-Crystal SmMn2Ge2

Magnetic materials with noncollinear spin configurations have engendered significant interest in condensed matter physics due to their intriguing physical properties. We direct our attention towards the magnetic properties and critical behavior of single-crystal SmMn2Ge2, an itinerant magnet with numerous temperature-dependent magnetic phase transitions. Notably, SmMn2Ge2 displays significant magnetic anisotropy with easy magnetization direction switching from the c axis to the ab plane as temperature decreases. The critical behavior of the ferromagnetic transition occurring above room temperature is thoroughly examined. Reliable and self-consistent critical exponents, including beta = 0.292(2), gamma = 0.924(8), and delta = 4.164(6), along with the Curie temperature T (c) = 347 K, are extracted through various methods, which provide evidence for the coexistence of multiple magnetic interactions in SmMn2Ge2. Further analysis reveals that the magnetic interaction of SmMn2Ge2 is a long-range type with the interaction distance decaying as J(r) similar to r (-4.35).