講演情報
[14p-K302-13]Determination of coupling states of a spin-torque oscillator in an HDD head using injection locking
〇Yuji Nakagawa1, Hirofumi Suto2, Yuya Sakuraba2, Tomoyuki Maeda1 (1.Toshiba, 2.NIMS)
キーワード：
spin-torque oscillator (STO)、injection locking、microwave-assisted magnetic recording (MAMR)
We developed an analysis method of the coupling state in an STO (spin-torque oscillator) using injection locking and applied the method to an STO in a MAMR (microwave-assisted magnetic recording) HDD head, where an anti-parallel coupling of oscillation layers is desired for recoding. During the injection of an external microwave magnetic field, the STO resistance was monitored to detect injection locking. By comparing the results of spectrum and injection locking measurements, we found that the coupled state did not respond to the injected microwave field. On the other hand, the uncoupled state, where only one magnetic layer oscillates under the opposite current bias polarity, showed a clear injection locking. These results provide evidence of the coupled oscillation in the STO for MAMR and demonstrate the capability of our method to determine the coupling state.