Perpendicular Magnetic Anisotropy of Co\Pt bilayers on ALD HfO2

Perpendicular Magnetic Anisotropy (PMA) is a key requirement for state of the art Magnetic Random Access Memories (MRAM). Currently, PMA has been widely reported in standard Magnetic Tunnel Junction material stacks using MgO as a dielectric. In this contribution, we present the first report of PMA at the interface with a high-k dielectric grown by Atomic Layer Deposition, HfO2. The PMA appears after annealing a HfO2\Co\Pt\Ru stack in N2 with the Keff of 0.25 mJ/m² as determined by Vibrating Sample Magnetometry. X-Ray Diffraction and Transmission Electron Microscopy show that the appearance of PMA coincides with interdiffusion and the epitaxial ordering of the Co\Pt bilayer. High-k dielectrics are especially interesting for Voltage Control of Magnetic Anisotropy applications and are of potential interest for low-power MRAM and spintronics technologies.status: publishe