Anomalous Nernst effect in CO_x(MgO)_(1-x) granular thin films

摘要

The anomalous Nernst effect (ANE) is investigated for 100 nm Co_x(MgO)_(1-x) granular films as a function of the Co volume fraction (x) changes. The results show that by slightly adding MgO into the Co matrix, the anomalous Nernst angle (θ_(AN)) can be largely enhanced more than three times compared with that of pure Co, which also results in the obvious change in ANE voltage. The transverse conductivity σ_(XY)~(AH) vs the longitudinal conductivity σ_(XX) shows distinct linear behavior in three regimes, which indicates different anomalous Hall effect (AHE) mechanisms. By qualitative Mott-relation analysis, we found that the non-monotonic dependence of ANE on ⅹ is associated with the change in AHE mechanisms.