Next, the minor TMR loops for the three states are shown in FIG. 4B. The interlayer coupling field (HIC) is revealed by the center position of the loop (marked by arrows in FIG. 3b). The initial state of the interlayer coupling is negative (AFM), with HIC=?42 Oe. After the application of +VSET, two striking features emerge. First, HC′-TOP is dramatically reduced (from 150 Oe to 45 Oe), much more pronounced than the reduction of He-TOP (from 100 Oe to 80 Oe). Second and most surprisingly, the sign of the interlayer coupling is changed; namely, the coupling is now positive (FM) with HIC=+37 Oe. Remarkably, with the application of ?VSET, the center of the minor loop can be shifted back to the left, with an even more negative HIC of ?51 Oe. The results illustrated in FIG. 4B represent the first demonstration of VCIC in an MTJ system, where both the magnitude and sign of the interlayer coupling can be changed by applied voltage.
