Anomalous Nernst effect in stressed magnetostrictive film grown onto flexible substrate

Abstract

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.

Unraveling the role of magnetic anisotropy on the thermoelectric response: a theoretical and experimental approach

“…Moreover, the influence of the cubic magnetocrystalline anisotropy of Co58.73Fe27.83Al13.44 Heusler alloys, grown onto substrates with distinct orientations, on thermoelectric effects has been studied by the LSSE [25]. For both situations, the results corroborate that the thermoelectric curves are strongly dependent on the magnitude and orientation of the magnetic field with respect to the anisotropies [23][24][25]. In addition, the thermoelectric measurements may be yet used to probe the magnetic anisotropy, as well as to identify the field ranges in which the anisotropic and Zeeman energy terms represent the major contribution to the magnetic free energy density governing the magnetization process [25].…”

“…Through the appropriate selection of substrates and/or experimental deposition parameters, it is possible to induce/control the magnetic anisotropies of the FM system. Consequently, the thermoelectric response may be modified by both, the magnetic anisotropy and the orientation of the external magnetic field [23].…”

“…While the thermoelectric effects have been widely investigated from the theoretical perspective, the role of the magnetic anisotropy on thermoelectric effects has rarely been addressed, despite of its scientific and technological potential relevance [24]. Recently, the modifications of the magnetic properties and thermoelectric effects, as ANE, have been explored in flexible magnetostrictive Co40Fe40B20 thin films with induced uniaxial magnetic anisotropy and under external stress [23]. Moreover, the influence of the cubic magnetocrystalline anisotropy of Co58.73Fe27.83Al13.44 Heusler alloys, grown onto substrates with distinct orientations, on thermoelectric effects has been studied by the LSSE [25].…”

Spin‐Dependent Thermoelectric Transport in Cobalt‐Based Heusler Alloys

“…This can even be used to manufacture a flexible thermoelectric device. [171] The anomalous Nernst coefficient dependence of the obtainable electric power and power density shown in Figure 12c,d indicate the possibilities of using the ANE-based devices. Since materials having large Nernst coefficients at room temperature are obviously one of the crucial factors for prototyping such a ANE thermopile device, the Co-based Heusler alloys provide a good opportunity for realizing realistic devices due to their high level of tunability in terms of structural, electronic, and magnetic properties.…”

Modulating the Spin Seebeck Effect in Co2FeAl Heusler Alloy for Sensor Applications

“…In order to obtain further information of our system and estimate anisotropy constants, we considered the well-known angular resonance frequency ω r and linewidth of the resonance absorption ∆ω, which can be written as [24,48,49]…”