Determination of Thermal Stability of Magnetic Tunnel Junction Using Time-Resolved Single-Shot Measurement

Time-resolved single-shot measurement has been investigated to characterize switching times of the free layer in magnetic tunneling junctions (MTJs). In this study, a stacked MTJ film is patterned into an elongated, nano-scale device using standard electron beam lithography in conjunction with ion beam etching. Subsequently, current-induced magnetization switching is initiated using a single-shot measurement based on the time-domain transmission method. A current pulse with a duration of 50 ns is utilized to switch the magnetization configuration between parallel and anti-parallel states. After the pulse rises, the transmission profile shows a transition in which resistance varies. That is, the incubation time between pulse onset and resistance change represents the switching time of the free layer. The statistical distribution results of the switching times are obtained. The switching times are strongly dependent on current density and the external magnetic field. By fitting the data points using the Néel-Arrhenius law, the thermal stability factor J_Co and intrinsic current density J_Co are also determined.