Abstract Among the most important issues of Renormalization Group (RG) theory are crossover events and relevant (or non-relevant) interactions. These terms are unknown to atomistic theories but they will be decisive for future field theories of magnetism. In this experimental study the importance of these terms for the critical dynamics above and below magnetic ordering transition is demonstrated on account of new analyses of published data. When crossover events are overlooked and critical data are fitted by a single power function of temperature over a temperature range including a crossover event, imprecise critical exponents result. The rather unsystematic and floating critical exponents reported in literature seem largely to be due to this problem. It is shown that for appropriate data analyses critical exponents are obtained that are to a good approximation rational numbers. In fact, rational critical exponents can be expected when spin dynamics is controlled by the bosons of the continuous magnetic medium (Goldstone bosons). The bosons are essentially magnetic dipole radiation generated by the precessing spins. As a result of the here performed data analyses, critical exponents for the magnetic order parameter of β = 1/2, 1/3, 1/4 and 1/6 are obtained. For the critical paramagnetic susceptibility the exponents are γ = 1 and γ = 4/3.

中文翻译：

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磁序转变附近临界范围内的交叉现象

摘要 重整化群 (RG) 理论中最重要的问题是交叉事件和相关（或非相关）相互作用。这些术语对于原子理论来说是未知的，但它们对于未来的磁场理论将是决定性的。在这项实验研究中，由于对已发表数据的新分析，证明了这些术语对于磁序转变之上和之下的临界动力学的重要性。当忽略交叉事件并且在包括交叉事件的温度范围内通过温度的单一幂函数拟合关键数据时，会导致不精确的关键指数。文献中报道的相当不系统和浮动的关键指数似乎主要是由于这个问题。结果表明，对于适当的数据分析，获得的关键指数是一个很好的近似有理数。事实上，当自旋动力学由连续磁介质的玻色子（戈德斯通玻色子）控制时，可以预期有理临界指数。玻色子本质上是由进动自旋产生的磁偶极子辐射。作为此处执行的数据分析的结果，获得了磁序参数 β = 1/2、1/3、1/4 和 1/6 的临界指数。对于临界顺磁化率，指数为 γ = 1 和 γ = 4/3。玻色子本质上是由进动自旋产生的磁偶极子辐射。作为此处执行的数据分析的结果，获得了磁序参数 β = 1/2、1/3、1/4 和 1/6 的临界指数。对于临界顺磁化率，指数为 γ = 1 和 γ = 4/3。玻色子本质上是由进动自旋产生的磁偶极子辐射。作为此处执行的数据分析的结果，获得了磁序参数 β = 1/2、1/3、1/4 和 1/6 的临界指数。对于临界顺磁化率，指数为 γ = 1 和 γ = 4/3。