The van der Waals ferromagnet Fe₅GeTe₂ has a Curie temperature T_C of about 270 K, which is tunable through controlling the Fe deficiency content and can even reach above room temperature. To achieve insights into its ferromagnetic exchange that gives the high T_C, the critical behavior has been investigated by measuring the magnetization in Fe₅GeTe₂ crystal around the ferromagnetic ordering temperature. The analysis of the measured magnetization by using various techniques harmonically reached to a set of reliable critical exponents with T_C = 273.7 K, β = 0.3457 ± 0.001, γ = 1.40617 ± 0.003, and δ = 5.021 ± 0.001. By comparing these critical exponents with those predicted by various models, it seems that the magnetic properties of Fe₅GeTe₂ could be interpreted by a three-dimensional magnetic exchange with the exchange distance decaying as J(r) ≈ r^−4.916, close to that of a three-dimensional Heisenberg model with long-range magnetic coupling.

范德华铁磁体Fe ₅ GeTe ₂的居里温度T _C约为270 K，可通过控制缺铁含量进行调节，甚至可以达到室温以上。为了深入了解其产生高T _C的铁磁交换，已通过测量 Fe ₅ GeTe ₂晶体在铁磁有序温度附近的磁化强度来研究其临界行为。通过使用各种技术对测量的磁化强度进行分析，谐波达到一组可靠的临界指数，T _C  = 273.7 K，β  = 0.3457 ± 0.001，γ = 1.40617 ± 0.003，δ  = 5.021 ± 0.001。通过将这些关键指数与各种模型预测的指数进行比较，似乎 Fe ₅ GeTe ₂的磁性可以通过三维磁交换来解释，交换距离衰减为J ( r ) ≈  r ^-4.916，接近具有长程磁耦合的三维海森堡模型。