Grad Talk: Study on Voltage Controlled Magnetic Anisotropy Effect

Abstract: Electric-field-induced control of magnetic properties has attracted much attention in recent years due to its promising potential for ultralow energy consumption electric devices. The voltage-controlled magnetic anisotropy (VCMA) effect in the magnetic tunnel junction (MTJ) has demonstrated that the magnetization can be controlled by the electric field. However, the applied electric field is limited to 0.5V/nm in most cases to avoid the breakdown of the tunnel barrier. In this study, a unique probe station equipped with a pulse voltage source is employed to investigate the VCMA effect under a high electric field in the region above 1V/nm. During the experiment, we found an unexpected magnetoresistance (MR) under high voltage and our next step is to figure out the cause and try to eliminate the unexpected MR. In addition, Grezes et al [1] and Kanai et al [2] experimentally show low writing energy of around 6 fJ in high resistance MTJs, and another research project of mine is to realize writing energy as low as 1 fJ in the VCMA-controlled precessional switching.

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