Abstract We studied the frequency-dependent (f = 1 GHz to 5 GHz) microwave absorption in the double perovskite La2NiMnO6 at room temperature using two cavity-less methods: An indirect impedance method that uses a radio frequency impedance analyzer and a folded copper strip coil for the frequency range f = 1 to 2.2 GHz and a lock-in based broadband setup using a coplanar waveguide for microwave excitation in the frequency range f = 2 to 5 GHz. The high-frequency resistance of the strip coil exhibits a sharp peak and the reactance curve crosses zero at a critical value of dc magnetic field as a consequence of the paramagnetic resonance in the sample. The resonance fields (Hr) obtained from both the techniques increase linearly with frequency. Line shape analysis and analytical fitting were performed to characterize the material in terms of its initial susceptibility and damping parameters. From the fit, we obtain a large spectroscopic g-factor, equal to 2.1284, which supports the presence of Ni2+ cation with strong spin-orbit coupling.

中文翻译：

---

通过阻抗和锁定检测技术探测 La2NiMnO6 中的顺磁共振

摘要 我们使用两种无腔方法研究了室温下双钙钛矿 La2NiMnO6 的频率相关（f = 1 GHz 至 5 GHz）微波吸收：一种使用射频阻抗分析仪和折叠铜带线圈的间接阻抗方法对于频率范围 f = 1 至 2.2 GHz 和基于锁定的宽带设置，使用共面波导在频率范围 f = 2 至 5 GHz 中进行微波激发。由于样品中的顺磁共振，带状线圈的高频电阻呈现出尖峰，电抗曲线在直流磁场的临界值处与零交叉。从这两种技术获得的共振场 (Hr) 随频率线性增加。执行线形分析和解析拟合以根据材料的初始磁化率和阻尼参数表征材料。从拟合中，我们获得了一个大的光谱 g 因子，等于 2.1284，它支持具有强自旋轨道耦合的 Ni2+ 阳离子的存在。