1)MR dependence on temperature: a)Movement of switching fields from overlapping H=0 at high temp to separated and apart at low temp. (working theory: VT interlayer has extra spins causing AF coupling at high temp state) b)MR dependence on temp: increases as expected when temp. decreases c)Thermal hysteresis: Switching field movements (described above in a) have a temperature history (quantitatively different behaviors based on different cooling runs – working theory: thermal quenching) 2)MR dependence on bias (I-V shows interface dipoles are present): a)Non-monotonic MR effect based on bias in G-V plots (never been seen before) a)Off-zero peak of G-V b)Bias direction dependence of magnetic sweeps b)Hysteretic pockets in the G-V curves (working theory: trapped spin states in low-spin VT) c)At low temp, the switching field movement (towards H=0) can also be driven by a higher bias (higher energy causes reversion back to high spin?) 3)Light: At low temp, light can cause transition back to AF coupling behavior (switching fields move back across H=0 – consistent with transition back to high-spin state) List of Key Findings for VT Paper from sample CC

Figure 1: Switching Fields change as a function of temperature At high temp, coercive fields overlap (AF coupling via extra spins in the high-spin Co II form of the molecule). At low temp, the layers are again switching independently (no coupling in the low-spin Co III form of VT). Figure 1

Figure 2 Figure 2: Non-monotonic MR as a function of bias. Also shown are hysteretic trapped states.

Figure 3: Light experiment at 80K. Turning on the laser causes the AF coupling to return. Figure 3