講演情報
[14p-K302-12]Size-Dependent Dynamic Properties of Stochastic Magnetic Tunnel Junction with a Synthetic Antiferromagnetic Free Layer
〇(M1)Takuma Kinoshita1, Ju-Young Yoon1, Nuno Cacoilo1, Haruna Kaneko1, Shun Kanai1, Hideo Ohno1, Shunsuke Fukami1 (1.Tohoku Univ.)
キーワード：
magnetic tunnel junction、probabilistic computer
Probabilistic computers (p-computers) consisting of stochastic magnetic tunnel junctions (s-MTJs) have emerged as a candidate for energy-efficient computers suitable for complex tasks. For fast and reliable computation, s-MTJs require a high robustness against external fields and a short relaxation time . In this study, we investigate the size dependence of the external field robustness and relaxation time in circular s-MTJs with a synthetic antiferromagnetic (SAF) free-layer. The stack of s-MTJ consists of, from the substrate side, Ta (5)/PtMn (20)/Co (2.00)/Ru (0.85)/CoFeB (2.20)/MgO (1.10)/CoFeB (1.80)/Ru (0.74)/CoFeB (2.34)/cap (nominal thicknesses in nm). The SAF-free layer consists of two CoFeB layers separated by the Ru layer, with their magnetizations compensating each other. We find that smaller s-MTJs exhibit shorter relaxation times and stronger field robustness, which are attributed to the reduced energy barrier between the AP and P states and the decreased Zeeman energy, respectively. This work provides guidelines for designing s-MTJs towards high-performance p-computers.