Moraitis Petros, Koutsokeras Loukas, Stamopoulos Dimosthenis
Department of Physics, School of Science, National and Kapodistrian University of Athens, Zografou Panepistimioupolis, 15784 Athens, Greece.
Materials (Basel). 2024 Apr 10;17(8):1744. doi: 10.3390/ma17081744.
The multifaceted inductive technique of AC magnetic susceptibility (ACMS) provides versatile and reliable means for the investigation of the respective properties of magnetic and superconducting materials. Here, we explore, both mathematically and experimentally, the ACMS set-up, based on four coaxial pick-up coils assembled in the second-derivative configuration, when employed in the investigation of differently shaped superconducting specimens of poly-crystalline YBaCuO and BiPbSrCaCuO and single-crystalline YBaCuO. Through the mathematical modeling of both the ACMS set-up and of linearly responding superconducting specimens, we obtain a closed-form relation for the DC voltage output signal. The latter is translated directly to the so-called ACMS of the studied specimen. By taking into account the specific characteristics of the studied high-T specimens (such as the shape and dimensions for the demagnetizing effect, porosity for the estimation of the superconducting volume fraction, etc.), we eventually draw the truly ACMS of the parent material. Importantly, this is carried out without the need for any calibration specimen. The comparison of the mathematical modeling with the experimental data of the aforementioned superconducting specimens evidences fair agreement.
交流磁化率（ACMS）的多方面归纳技术为研究磁性和超导材料的各自特性提供了通用且可靠的方法。在此，我们在数学和实验上探索了基于以二阶导数配置组装的四个同轴拾取线圈的ACMS装置，该装置用于研究多晶YBaCuO和BiPbSrCaCuO以及单晶YBaCuO的不同形状的超导样品。通过对ACMS装置和线性响应超导样品进行数学建模，我们得到了直流电压输出信号的闭式关系。后者直接转换为所研究样品的所谓交流磁化率。通过考虑所研究的高温样品的特定特性（例如去磁效应的形状和尺寸、用于估计超导体积分数的孔隙率等），我们最终得出母体材料的真实交流磁化率。重要的是，这一过程无需任何校准样品。数学建模与上述超导样品的实验数据的比较证明了良好的一致性。
