论文标题
基于磁抑制的L波段电子顺磁共振的检测2,2-二苯基-1-苯基氢羟基（DPPH）分子
Magnetoimpedance based detection of L-band electron paramagnetic resonance in 2,2-diphenyl-1-picrylhydrazyl (DPPH) molecule
论文作者
论文摘要
迄今为止，使用以固定频率（9至10 GHz之间）共鸣的微波腔检测电子顺磁共振（EPR）仍然是最流行的方法。在这里，我们报告了一种无腔技术技术，该技术仅使用阻抗分析仪和铜带线圈来检测标准EPR标记物2,2-二苯基-1-苯基-Picrylhydrazyl（DPPH）的L波段EPR（F = 1-3 GHz）。我们的方法依赖于测量DPPH通过包围DPPH的铜带线圈的磁性阻抗（MI）响应。与仅测量功率吸收场导数的商业EPR相反，我们的方法使我们能够推断出吸收和分散。扫描外部直流磁场时的电阻（r）和电抗（x）的变化，测量了线圈中射频电流的不同频率（F = 0.9至2.5 GHz）。 R在直流磁场的临界值下表现出尖锐的峰，该峰值被识别为共振场，X在相同频率下显示分散体。分析数据以获得线宽度和共振场参数。共振场随频率线性增加，而获得的landéG系数为1.999接近2.0036的可接受值，以x波段测量。可以利用该技术的简单性来研究催化和其他材料中的顺磁中心。
Detection of electron paramagnetic resonance (EPR) using a microwave cavity resonating at a fixed frequency (between 9 and 10 GHz) remains the most popular method until now. Here, we report a cavity-less technique which makes use of only an impedance analyzer and a copper strip coil to detect L-band EPR (f = 1-3 GHz) in the standard EPR marker 2,2-diphenyl-1-picrylhydrazyl (DPPH). Our method relies on measuring the magnetoimpedance (MI) response of DPPH through a copper strip coil that encloses DPPH. In contrast to commercial EPR which measures only the field derivative of power absorption, our method enables us to deduce both absorption and dispersion. Changes in resistance (R) and reactance (X) of the copper strip while sweeping an external dc magnetic field, were measured for different frequencies (f = 0.9 to 2.5 GHz) of radio-frequency current in the coil. R exhibits a sharp peak at a critical value of the dc magnetic field, which is identified as the resonance field and X shows a dispersion at the same frequency. The data were analyzed to obtain line width and resonance field parameters. The resonance field increased linearly with frequency and the obtained Landé g factor of 1.999 is close to the accepted value of 2.0036, measured in X-band. The simplicity of this technique can be exploited to study paramagnetic centers in catalysis and other materials.
