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. decreasesc) 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-Vb) 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 Paperfrom sample CC149

5-19-12

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