The Magnetic Properties on the MgO/CoFeB/Ta/Co/Pt structures

Abstract

At the interface between a heavy metal (HM) and a ferromagnet (FM), interfacial phenomena such as an interfacial perpendicular magnetic anisotropy (iPMA), interfacial Dzyaloshinskii-Moriya interaction (iDMI) appear because of their strong spin-orbit coupling (SOC) [1]. The element with large SOC strength as an interface at the HM/FM may provide a large modulation of the iPMA and iDMI values. Furthermore, there are numerous studies that the orbital hybridization at the interface between FM and the oxide layer can improve the iPMA for developing magnetoresistive random access memory with high thermal stability [2]. In this study, we investigate the Co layer thickness dependent magnetic properties on the MgO (5 nm)/ Co40Fe40B20 (0.6 nm)/Ta (0.2 nm)/Co (0.8, 1.0, 1.2, 1.4, 1.6, 1.8 nm)/Ta (5 nm) structure fabricated by magnetron sputtering system. Furthermore, to investigate the annealing effect of MgO/CoFeB/Ta layer, the series of samples were annealed at 300 o C, 1hour. The systematic Brillouin light scattering measurements are performed for the fabricated sample to investigate magnetic properties. As shown in Table 1, the determined values of saturation magnetization (Ms), iPMA energy (Ks), and normalized iDMI energy density (Ds) of 300 o C annealed samples are increased by 30 % (compare with as-deposited samples). These results can open a new path to spintronic devices.