Magnetic switching fluctuations from sidewall oxides in MgO/FeCoB magnetic tunnel junctions

Abstract

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 . In both cases, the MR-FORC data exhibit a prominent checkerboard pattern that implies coupling to magnetic oxides on the MTJ sidewalls. © 2011 American Institute of Physics.