Alam Junaid, Nematov Makhsudsho, Yudanov Nikolay, Podgornaya Svetlana, Panina Larissa
Institute of Novel Materials and Nanotechnology, National University of Science and Technology, MISiS, 119991 Moscow, Russia.
Institute of Physics, Mathematics & IT, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia.
Nanomaterials (Basel). 2021 May 2;11(5):1208. doi: 10.3390/nano11051208.
Magnetoimpedance (MI) in Co-based microwires with an amorphous and partially crystalline state was investigated at elevated frequencies (up to several GHz), with particular attention paid to the influence of tensile stress on the MI behavior, which is called stress-MI. Two mechanisms of MI sensitivity related to the DC magnetization re-orientation and AC permeability dispersion were discussed. Remarkable sensitivity of impedance changes with respect to applied tensile stress at GHz frequencies was obtained in partially crystalline wires subjected to current annealing. Increasing the annealing current enhanced the axial easy anisotropy of a magnetoelastic origin, which made it possible to increase the frequency of large stress-MI: for 90mA-annealed wire, the impedance at 2 GHz increased by about 300% when a stress of 450 MPa was applied. Potential applications included sensing elements in stretchable substrates for flexible electronics, wireless sensors, and tunable smart materials. For reliable microwave measurements, an improved SOLT (short-open-load-thru) calibration technique was developed that required specially designed strip cells as wire holders. The method made it possible to precisely measure the impedance characteristics of individual wires, which can be further employed to characterize the microwave scattering at wire inclusions used as composites fillers.
研究了具有非晶态和部分晶态的钴基微丝在高频（高达几吉赫兹）下的磁阻抗（MI），特别关注拉伸应力对MI行为的影响，即应力磁阻抗。讨论了与直流磁化重新取向和交流磁导率色散相关的MI灵敏度的两种机制。在经过电流退火的部分晶态微丝中，在吉赫兹频率下获得了阻抗变化相对于施加拉伸应力的显著灵敏度。增加退火电流增强了磁弹性起源的轴向易磁化轴各向异性，这使得增加大应力磁阻抗的频率成为可能：对于90mA退火的微丝，当施加450MPa的应力时，2GHz处的阻抗增加了约300%。潜在应用包括用于柔性电子、无线传感器和可调谐智能材料的可拉伸基板中的传感元件。为了进行可靠的微波测量，开发了一种改进的SOLT（短路-开路-负载-直通）校准技术，该技术需要专门设计的带状单元作为微丝固定器。该方法使得精确测量单根微丝的阻抗特性成为可能，这些特性可进一步用于表征用作复合材料填料的丝状夹杂物处的微波散射。
