The spin dynamics of {Cr₈Y₈}, a rare example of ferromagnetic molecular rings, has been studied by inelastic neutron scattering (INS) and heat capacity (HC) methods. Clear evidence of low-lying magnetic excitation has been found. Magnetic Schottky anomalies are observed in low-temperature (low-T) HC curves measured under various fields and can be well fitted with a multi-level Schottky term, giving important information on the energy gaps between spin levels. The INS results obtained on TOFTOF and NEAT time-of-flight spectrometers show INS peaks corresponding to the transitions within S = 12 ground states and between the S = 12 ground state and the S = 11 excited state. The single-J model with a unique exchange constant J = 0.151 meV can well reproduce the low-lying energy levels and their Zeeman splitting upon applied magnetic fields. This work shows that the single-J model can be a good approach for the low-T spin dynamics of {Cr₈Y₈} and may have general significance for other weak ferromagnetic molecular rings. Determination of the Cr³⁺-Cr³⁺ exchange constant in {Cr₈Y₈} will benefit the study on the complicated magnetic interactions in chromium lanthanide complexes. The zero-field splitting which is suggested by HC data still calls for EPR or high-resolution INS technique to verify.

通过非弹性中子散射（INS）和热容（HC）方法研究了{Cr ₈ Y ₈ }的自旋动力学，这是铁磁分子环的一个罕见例子。已发现低地磁激发的明确证据。在各种场下测得的低温（low- T）HC曲线中观察到了磁性肖特基异常，可以很好地拟合多级肖特基项，从而提供有关自旋能级之间的能隙的重要信息。在TOFTOF和NEAT飞行时间光谱仪上获得的INS结果显示INS峰对应于S  = 12基态和S  = 12基态与S  = 11激发态之间的跃迁。单具有唯一交换常数J  = 0.151 meV的J模型可以很好地重现低位能级及其在施加磁场时的塞曼分裂。这项工作表明，单J模型对于{Cr ₈ Y ₈ }的低T自旋动力学可能是一种很好的方法，并且可能对其他弱铁磁分子环具有普遍意义。{Cr ₈ Y ₈中的Cr ³⁺ -Cr ³⁺交换常数的测定}将有助于研究镧系元素铬络合物中复杂的磁性相互作用。HC数据建议的零场分裂仍然需要EPR或高分辨率INS技术进行验证。