在用样品电流模式的测量过程中发现,磁场强度、磁场与样品表面的夹角以及光斑在样品表面的位置都会对吸收谱强度产生影响;在光斑、磁场和样品的不同几何配置下,测量并分析了表面均匀氧化的铝箔中氧的K边吸收谱,指出外磁场下吸收谱强度随各种条件变化的趋势,并对实验结果给出了合理解释;结果表明所用的模型分析与实验数据符合得很好;所得到的信息对于XMCD实验的设计安排、相应数据的分析以及物理信息的提取具有重要意义.
In the measurement of X-ray magnetic circular diehroism (XMCD) spectra, external magnetic field is required during experiment. We have found that, if the X-ray absorption spectra are recorded using drain current, the spectrum intensity is strongly influenced by external magnetic field. The normalized signal intensity changes with the value of the deviation angle between magnetic field and sample surface, the amount of the external inagnetie field and the relative position of beam spot on sample surface. In this paper, the K edge absorption spectra of oxygen contained in aluminum foil are measured in different magnetic field configurations. The variation trends of signal intensity with the change in various external parameters are indicated, and reasonable explanations have been given. The experimental data are well accordance with their corresponding fitting curves, suggesting that the model constructed in this paper is applicable for solving this problem. The article provides a basis for analyzing the effects of external field on drain current signal.