Speakers
Description
The Voltage Control of Magnetic Anisotropy (VCMA) effect allows to control a magnetic bit by means of an electric field [1] instead of high currents, enabling a much lower power consumption. State-of-the-art Magnetic Tunnel Junction (MTJ) material stacks using mostly MgO as a dielectric have been screened for VCMA applications [1,2]. The MgO VCMA effect is currently too weak for use in logic and memory applications. We aim to obtain an electronic VCMA effect rather than an ionic effect, which would be too slow for nanoelectronics applications. The use of high-κ dielectrics promises to allow a giant electronic VCMA effect, opening the door to low power voltage-controlled nanoelectronics.
We aim at investigating high-κ dielectrics for giant VCMA applications. The first step for obtaining VCMA on Atomic Layer Deposition (ALD) high-κ dielectrics is tailoring the magnetic anisotropy, for which no work has been done. The use of ALD dielectrics is key for obtaining good insulating and reliability properties to sustain electric fields. Our work so far has focused on HfO2 in combination with different ferromagnet\nonmagnet bilayers, such as Co\Pt, CoFeB\Ta and CoFe\Ta. We show that Perpendicular Magnetic Anisotropy (PMA) can be obtained in all three multilayers.
[1] Maruyama, T., Y. Shiota, T. Nozaki, K. Ohta, N. Toda, M. Mizuguchi, A. A. Tulapurkar, T. Shinjo, M. Shiraishi, S. Mizukami, Y. Ando, Y. Suzuki . Nature nanotechnology 4, 158 (2009) [2] Kita, Koji, David W. Abraham, Martin J. Gajek, and D. C. Worledge. J. Appl. Phys 112, 033919 (2012)
