Room temperature giant magnetostriction in single-crystal nickel nanowires
Room temperature giant magnetostriction in single-crystal nickel nanowires
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DOI：
10.1038/s41427-019-0160-8
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发表时间：
2019-10-18
影响因子：
9.7
通讯作者：
Fohtung, Edwin
中科院分区：
文献类型：
--
作者：
Pateras, Anastasios;Harder, Ross;Fohtung, Edwin
磁致伸缩是由外部磁场引起的机械变形的出现。在纳米尺度下通过磁致伸缩将磁能转换为机械能是许多机电系统（例如传感器、换能器、致动器和能量采集器）的基础。然而，通常需要低温和大磁场来驱动这种系统中的磁致伸缩，使得这种方法在能量上效率低下并且对于室温器件应用不切实际。在这里，我们报告的实验观察到的巨磁致伸缩单晶镍纳米线在室温下。我们确定的平均值的磁致伸缩常数的Ni纳米线从使用002和111布拉格反射测量的衍射图案的移位。在600 Oe的外加磁场下，磁致伸缩常数的值为λ（100）= -0.161%和λ（111）=-0.067%，比块体镍中的磁致伸缩常数大两个数量级。使用布拉格相干衍射成像（BCDI），我们得到了三维应变分布内的Ni纳米线，揭示了在两个不同的值的外部磁场的局部应变场的成核。我们的分析表明，磁致伸缩系数的增强主要是由于形状的增加，表面诱导，和应力诱导的各向异性，这有利于磁化沿着纳米线轴，并增加了系统的总磁弹性能量。
Magnetostriction is the emergence of a mechanical deformation induced by an external magnetic field. The conversion of magnetic energy into mechanical energy via magnetostriction at the nanoscale is the basis of many electromechanical systems such as sensors, transducers, actuators, and energy harvesters. However, cryogenic temperatures and large magnetic fields are often required to drive the magnetostriction in such systems, rendering this approach energetically inefficient and impractical for room-temperature device applications. Here, we report the experimental observation of giant magnetostriction in single-crystal nickel nanowires at room temperature. We determined the average values of the magnetostrictive constants of a Ni nanowire from the shifts of the measured diffraction patterns using the 002 and 111 Bragg reflections. At an applied magnetic field of 600 Oe, the magnetostrictive constants have values of lambda(100) = -0.161% and lambda(111) = -0.067%, two orders of magnitude larger than those in bulk nickel. Using Bragg coherent diffraction imaging (BCDI), we obtained the three-dimensional strain distribution inside the Ni nanowire, revealing nucleation of local strain fields at two different values of the external magnetic field. Our analysis indicates that the enhancement of the magnetostriction coefficients is mainly due to the increases in the shape, surface-induced, and stress-induced anisotropies, which facilitate magnetization along the nanowire axis and increase the total magnetoelastic energy of the system.