15:15 〜 15:30
▼ [5p-C18-9] Write error rate reduction in voltage-driven magnetization switching by a precise shape control of voltage pulse
キーワード：Voltage-controlled magnetic anisotropy, Magnetization switching, Ultrathin ferromagnetic films
Voltage-controlled magnetic anisotropy (VCMA) has brought a great advance in ultralow-energy manipulation of magnetization in ferromagnetic ultrathin films. The phenomenon was readily applied for the induction of magnetization switching in magnetic tunnel junctions (MTJs) by utilizing sub-nanosecond voltage pulses, showing a potential application for non-volatile magnetic random access memories (MRAMs).
In order to realize the voltage-controlled MRAMs, it is necessary not only to enhance the VCMA effect but also to improve the write error rate (WER) of each memory cell. Our group recently investigated WER in perpendicularly-magnetized MTJs (p-MTJs) and reported a WER of ~ 4 × 10-3, followed by an even lower WER of ~ 2 × 10-5 in a Ta/(Co31Fe69)80B20 (1.1 nm)/MgO structure. These reports would be a guideline for designing p-MTJs with low WER. In this work, we try to reduce WER by handling the magnetization dynamics through the controlled voltage pulses. Especially, by varying the rise time (τrise) and fall time (τfall) as well as the duration time (τpulse) of the voltage pulses, we study influences of the magnetization excitation/relaxation processes on WER.
In order to realize the voltage-controlled MRAMs, it is necessary not only to enhance the VCMA effect but also to improve the write error rate (WER) of each memory cell. Our group recently investigated WER in perpendicularly-magnetized MTJs (p-MTJs) and reported a WER of ~ 4 × 10-3, followed by an even lower WER of ~ 2 × 10-5 in a Ta/(Co31Fe69)80B20 (1.1 nm)/MgO structure. These reports would be a guideline for designing p-MTJs with low WER. In this work, we try to reduce WER by handling the magnetization dynamics through the controlled voltage pulses. Especially, by varying the rise time (τrise) and fall time (τfall) as well as the duration time (τpulse) of the voltage pulses, we study influences of the magnetization excitation/relaxation processes on WER.