L10 FePt, SOT, Inversion asymmetry, Magnetic switching, Perpendicular anisotropy, Engineering (General). Civil engineering (General), TA1-2040

In this study, current-induced partial magnetization-based switching was realized through the spin–orbit torque (SOT) in single-layer L10 FePt with a perpendicular anisotropy (Ku⊥) of 1.19 × 107 erg·cm−3 (1 erg·cm−3 = 0.1 J·m−3), and its corresponding SOT efficiency (βDL) was 8 × 10−6 Oe·(A·cm−2)−1 (1 Oe = 79.57747 A·m−1), which is several times higher than that of the traditional Ta/CoFeB/MgO structure reported in past work. The SOT in the FePt films originated from the structural inversion asymmetry in the FePt films since the dislocations and defects were inhomogeneously distributed within the samples. Furthermore, the FePt grown on MgO with a granular structure had a larger effective SOT field and efficiency than that grown on SrTiO3 (STO) with a continuous structure. The SOT efficiency was found to be considerably dependent on not only the sputtering temperature-induced chemical ordering but also the lattice mismatch-induced evolution of the microstructure. Our findings can provide a useful means of efficiently electrically controlling a magnetic bit that is highly thermally stable via SOT.