Melo Acácio Silveira, Oliveira Alexandre Barbosa de, Chesman Carlos, Della Pace Rafael Domingues, Bohn Felipe, Correa Marcio Assolin
Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900, Natal, RN, Brazil.
Sci Rep. 2019 Oct 25;9(1):15338. doi: 10.1038/s41598-019-51971-7.
The anomalous Nernst effect in nanostructured magnetic materials is a key phenomenon to optimally control and employ the internal energy dissipated in electronic devices, being dependent on, for instance, the magnetic anisotropy of the active element. Thereby, here, we report a theoretical and experimental investigation of the magnetic properties and anomalous Nernst effect in a flexible magnetostrictive film with induced uniaxial magnetic anisotropy and under external stress. Specifically, we calculate the magnetization behavior and the thermoelectric voltage response from a theoretical approach for a planar geometry, with magnetic free energy density that takes into account the induced uniaxial and magnetoelastic anisotropy contributions. Experimentally, we verify modifications of the effective magnetic anisotropy by changing the external stress, and explore the anomalous Nernst effect, a powerful tool to investigate the magnetic properties of magnetostrictive materials. We find quantitative agreement between experiment and numerical calculations, thus elucidating the magnetic behavior and thermoelectric voltage response. Besides, we provide evidence to confirm the validity of the theoretical approach to describe the magnetic properties and anomalous Nernst effect in ferromagnetic magnetostrictive films having uniaxial magnetic anisotropy and submitted to external stress. Hence, the results place flexible magnetostrictive systems as promising candidates for active elements in functionalized touch electronic devices.
纳米结构磁性材料中的反常能斯特效应是优化控制和利用电子设备中耗散的内能的关键现象，它取决于例如活性元件的磁各向异性。因此，在此我们报告了对具有诱导单轴磁各向异性且处于外部应力下的柔性磁致伸缩薄膜的磁性和反常能斯特效应的理论与实验研究。具体而言，我们从平面几何结构的理论方法出发，计算了考虑诱导单轴和磁弹各向异性贡献的磁自由能密度下的磁化行为和热电电压响应。在实验中，我们通过改变外部应力来验证有效磁各向异性的变化，并探索反常能斯特效应，这是研究磁致伸缩材料磁性的有力工具。我们发现实验与数值计算之间存在定量一致性，从而阐明了磁行为和热电电压响应。此外，我们提供证据证实了描述具有单轴磁各向异性并承受外部应力的铁磁磁致伸缩薄膜的磁性和反常能斯特效应的理论方法的有效性。因此，这些结果使柔性磁致伸缩系统成为功能化触摸电子设备中活性元件的有前途的候选者。
