SNR Improvement of Envelope Demodulation Using Two Tem-poral Magnetization Dynamics from Dual Spin-Torque Oscillator

Three-dimensional magnetic recording using microwave assisted magnetic recording (MAMR) has been proposed as one of the prospective recording technologies which uses a spin-torque oscillator (STO) as a reading sensor as well as a write-assisting device [1]. In the reading process using an STO, the reproducing waveform is given as temporal dynamics of magnetization [2]. The amplitude of STO oscillation waveform decreases as the STO comes close to the recorded dot of “0”, and the amplitude increases again as it leaves from the recorded dot of “0” [3]. The recorded dot “1” few influence on the amplitude. Therefore, we cannot discriminate whether the dead dot or recorded dot of “1”. However, the STO which reacts to the recorded dot of “1” can be produced by adjusting the resistance, the direct current, the external magnetic field, and so on [4]. In this research, we propose the envelope demodulation using two temporal magnetization dynamics from dual STO, and evaluate the bit error rate (BER) performance of R/W channel with dual STO by the computer simulation.