Dependence of the spin transfer torque switching current density on the exchange stiffness constant

We investigate the dependence of the switching current density on the exchange stiffness constant in the spin transfer torque magnetic tunneling junction using micromagnetic simulations. Since the widely accepted analytic expression of the switching current density is based on the macrospin model, there is no dependence on the exchange stiffness constant. However, we found strong dependence of the switching current density on the exchange stiffness constant because of the formation of complex spin configurations.