Magnetic switching fluctuations from sidewall oxides in MgO/FeCoB magnetic tunnel junctions
Joshua M. Pomeroy, J C. Read
Sharp magnetic switching distributions with coupling to magnetic sidewall oxides in FeCoB/MgO magnetic tunnel junctions (MTJs) are revealed by magneto-resistance first order reversal curve (MR-FORC) measurements. Tunneling magneto-resistance (TMR) and FORC data in units of % TMR/mT2 are shown for two identical devices that differ only by the annealing. The annealed sample has much larger TMR and correspondingly higher switching density q. In both cases, the MR-FORC data exhibit a prominent checkerboard pattern that implies coupling to magnetic oxides on the MTJ sidewalls.