In order to address the high demand for data in information technology, spintronics proposes attractive solutions. They are mainly based on the exploitation of the spin-orbit coupling of heavy metals to use the spin-orbit torque (SOT) exerted on the magnetic layers attached to the heavy metal. An example of this concept is presented in the W/CoTb/AlOx system. Here, as the resistivities of the W and CoTb are similar, we introduce a new characteristic temperature, T_switch, which is higher than the magnetic and angular compensation temperatures and lower than the Curie temperature [1].

However, magnetic material can be a source of spin current as well. In GdFeCo, we can identify spin currents of two different symmetries, SAHE-like [2,3] and SHE-like[4] corresponding respectively to the symmetries of the Spin Anomalous Hall Effect and Spin Hall Effect [5]. We report giant SAHE in GdFeCo amorphous ferrimagnetic thin films. Overall efficiency is 25 times more important in GdFeCo/Cu/NiFe than in Pt/Cu/NiFe. Furthermore, we compare the self-torque in GdFeCo/Cu with torques induced by Pt or Ta in Pt/Cu/GdFeCo and Ta/Cu/GdFeCo structures. This paves the way for new architectures to achieve and exploit heavy metal free SOT switching and skyrmions manipulation [5].

[1] Thai-Ha Pham et al. Phys. Rev. Appl. 9, 064032 (2018). ArXiv: 1711.10790
[2] T. Taniguchi et al., Phys. Rev. Appl. 3, 044001 (2015).
[3] S. Ihama et al., Nat. Elecron. 1, 120 (2018).
[4] Amin et al. J. Appl. Phys. 128, 151101 (2020).
[5] David Céspedes-Berrocal et al. Adv. Materials https://doi.org/10.1002/adma.202007047 (2020). ArXiv: 2010.09137