# Optimization of Bifurcated Switching by Enhanced Synthetic Antiferromagnetic Layer
[PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (J.G. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [EMAIL_ADDRESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (J.G. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [EMAIL_ADDRESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (G.J. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [EMAIL_ADDRESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (J.G. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [EMAIL_ADDRESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (J.G. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [EMAIL_ADDRESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (F.M. ); [EMAIL_ADDRESS] (Y.G. ); [EMAIL_ADDRESS] (R.C. ); [EMAIL_ADDRESS] (L.Z. ); [EMAIL_ADDRESS] (D.Z. ); [EMAIL_ADDRESS] (T.F. ); [PERSON]RESS] (W.H.) [PERSON]  
2 Zhejiang Hikistor Technology Company Ltd., Hangzhou 311300, China; [EMAIL_ADDRESS] (F.M. energy barrier of the RL can reduce or eliminate the impact of back-hopping on the write margin. Another failure phenomenon that erodes the write margin is the existence of a second switching branch of the WER curve at a lower WER level [17; 18]. Such branching behavior is called low-probability bifurcated switching (LPBS) or the balloon effect, which is highly reproducible [19]. The appearance of LPBS is strongly related to the spatial uniformity of the free-layer magnetization. The root cause of LPBS is highly noncoherent and complex and has been attributed to spatially varying spin textures in the free-layer magnet, for example, sub-volume excitations [20] and higher-order spin-wave modes [19]. The branching of the WER can be improved by reducing the size, raising the temperature, and increasing the pulse width [21; 22; 23]. However, all of these have side effects in MRAM applications. The operating temperature range and pulse width were fixed for a specific application, making it clear that adjusting these factors would not be an effective means of improving the balloon effect. It should be noted that reducing the size of the MTJ cell would inevitably result in a significant decrease in data retention, as indicated by \(\Delta=M_{\mathrm{S}}H_{K}V/2\). Therefore, more and more attention was focused on adjusting the free layer, optimizing the LPBS and improving the WER slopes [24; 25]. According to Fokker-Planck theory [26; 27], the cell with a larger \(\alpha\mathrm{H_{K}}\) value (where \(\alpha\) is the Gilbert damping coefficient and \(\mathrm{H_{K}}\) is the anisotropy field) has a smaller WER value at the same pulse width. However, both \(\alpha\) and \(H_{K}\) significantly increased the critical current density (\(J_{\mathrm{C}}\)), while \(\alpha\) weakened the spin-transfer-torque (STT) efficiency. Less insight into the influence of the reference layer (or SAF layer) on the WER was obtained, in addition to back-hopping [28]. Here, we attempted to eliminate the low-probability bifurcated-switching phenomenon in WER curves by introducing an enhanced SAF layer in our pMTJ stack. To eliminate the effects of the free layer and offset field on the WER, the free layer and the ferromagnetic layer in the SAF were considered to be the same.