Telegraph noise mechanism and LLG noise model

A preliminary study on random telegraph noise (RTN) is made. RTN is defined as the magnetization states switching by thermal fluctuations. State jumping resulting in baseline shift from the media field could also be RTN-associated multi-states switching. Our analysis shows that the root cause of such magnetization multi-states could be due to: (1) free layer edge states switching caused by a weak PM field; (2) surface and/or interface roughness, especially the lapped air bearing surface (ABS); and (3) random defects in the stack layers. A thermal noise model with Landau-Lifshitz-Gilbert equation (LLG) was developed and was applied to RTN demonstration.