Dutta Biswajit, Kumar Kranti, Ghodke N, Banerjee A
UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001, India.
Rev Sci Instrum. 2020 Dec 1;91(12):123905. doi: 10.1063/5.0029095.
An automated stepper motor controlled ac-susceptibility setup has been developed to measure the phase resolved linear and nonlinear magnetic ac-susceptibilities of a material in the temperature range of 4 K-300 K with a frequency range of 0.1 Hz-1.5 kHz. A maximum dc-field of ±150 Oe can be superimposed with a maximum ac-field of 100 Oe in the same coil by using a homemade ac-dc superimposing circuit. The induced voltage in the detection coil is measured by a lock-in amplifier, and temperature is controlled by a temperature controller. The very common offset voltage drifting problem is resolved by implementing a two-point measurement technique at every temperature, field, and frequency using a stepper motor. Operation of the stepper motor is controlled by a homemade computer programmable driver circuit. Sensitivity of the setup is obtained around ∼10 emu, and relative accuracy of the measurement is much better than 0.1%. Higher harmonics can be measured with a maximum noise level of ±15 nV throughout the temperature, field, and frequency range.
已开发出一种由自动步进电机控制的交流磁化率测量装置，用于在4 K至300 K的温度范围内、0.1 Hz至1.5 kHz的频率范围内测量材料的相位分辨线性和非线性交流磁化率。通过使用自制的交直流叠加电路，在同一线圈中可叠加最大±150 Oe的直流场和最大100 Oe的交流场。检测线圈中的感应电压由锁相放大器测量，温度由温度控制器控制。通过在每个温度、场和频率下使用步进电机实施两点测量技术，解决了非常常见的偏置电压漂移问题。步进电机的运行由自制的计算机可编程驱动电路控制。该装置的灵敏度约为10 emu，测量的相对精度远优于0.1%。在整个温度、场和频率范围内，可测量高次谐波，最大噪声水平为±15 nV。
