Magnetization dynamics in Ni nanostripes induced by surface acoustic waves
| Autor: | Castilla, D., Prieto, J. L., Muñoz Sánchez, Manuel, Sinusia, M., Fuentes, G., Lopez-Diaz, L., Yanes, R. |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Trabajo presentado en el 21st International Conference on Magnetism (ICM2018), celebrado en San Francisco (California, EE.UU.), del 15 al 20 de julio de 2018 The elastic deformation of a magnetic material has been proposed as an alternative source of energy to control the magnetization states and switching in nanoelements. [1], [2] [3]. In this work we fabricated a Surface Acoustic Wave (SAW) resonator [4] in close proximity to a 10 μm long Ni nanostripe of cross section 400 nm x 35 nm deposited by sputtering. The interdigital transducer (IDT) was fabricated by e-beam lithography on a 2 μm thick ScAlN piezoelectric film which was synthesized by reactive sputtering on a Si/SiO2 substrate. The Ni nanostripe was placed 45 μm away from the end of the IDT, with its axis in the direction of the traveling acoustic waves. Figure 1 shows the Anisotropic Magnetoresistance (AMR) response of the nanostripe for both no excitation in the IDT (black curve) and a power of +15 dBm (red curve). Although the field and the current are both in the direction of the nanostripe axis, there is significant AMR signal. Without any SAW excitation, after saturation with a positive field, the magnetization begins to rotate away from the stripe axis at about 70 Oe and the AMR signal drops gradual and reversibly. This reflects the polycrystalline nature of the sputtered Ni and the random orientation of the anisotropy axis. After reversing the external field at -20 Oe, there is an irreversible transition and the switching of the magnetization is completed at -42 Oe. When the IDT is powered with +15 dBm at its resonant frequency (1.25 GHz), the coercivity decreases noticeably. This can be expected as the movement of the domain walls is activated by the magnetolastic energy delivered by the SAWs [5] [6]. Strikingly, the return from saturation becomes irreversible. The inset to figure 1, shows a minor loop taken after the sudden drop of AMR at +8 Oe. This jump is irreversible, suggesting that a domain wall is injected in the nanostripe before reversing the external magnetic field, triggered by the magnetoelastic energy delivered by the SAW. These interesting results will be discussed in the light of additional micromagnetic simulations coupled to the magnetoelastic response of the system |
| Databáze: | OpenAIRE |
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