YNi₅ is an enhanced Pauli paramagnetic material, and this work is devoted to the effect of Co doping at the Ni site of YNi₅. It is found that at 10% Co doping, the sample turns ferromagnetic, with a weak itinerant character. The critical behaviours of the 10% Co‐doped sample (i.e., YNi_4.5CO_0.5) in its polycrystalline form are examined through bulk magnetization measurements. The second‐order phase transition from the paramagnetic to the ferromagnetic state is confirmed by the positive slope of the Arrott plots. To obtain the most reliable values of the critical exponents, an extensive analysis of the magnetization data is performed, which includes a modified Arrott plot, Kouvel–Fisher plot, and critical isotherm analysis. The best values of the exponent obtained are β = 0.179 (±0.002), γ = 1.429 (±0.002), and T_C = 9.1 K. These values are close to a 2D Ising model along with the long‐range exchange decaying as J(r) ≈ r^−(3.6). It is found that this extended exchange is a typical characteristic of many itinerant ferromagnets, whereas the 2D nature is likely to be connected with the layered crystal structure.

中文翻译：

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共掺杂YNi5中流动铁磁态的出现：相变的临界行为研究

YNi ₅是一种增强的Pauli顺磁性材料，这项工作致力于在YNi ₅的Ni部位进行Co掺杂。发现在钴掺杂量为10％时，样品变成铁磁性的，具有弱的流动特性。10％Co掺杂样品的临界行为（即YNi _4.5 CO _0.5通过体磁化测量来检查多晶形式的）。从顺磁状态到铁磁状态的二阶相变由Arrott图的正斜率确定。为了获得最可靠的临界指数值，需要对磁化数据进行广泛的分析，其中包括修正的Arrott图，Kouvel–Fisher图和临界等温线分析。获得的指数的最佳值是β  = 0.179（±0.002），γ  = 1.429（±0.002）和T _C  = 9.1K。这些值接近于二维Ising模型，并且长期交换衰减为J（ - [R）≈  - [R ^{- （3.6）}。已经发现，这种扩展的交换是许多迭代铁磁体的典型特征，而2D性质很可能与层状晶体结构有关。