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

Abstract

The anomalous Nernst effect (ANE) is investigated for 100 nm Cox(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 (θAN) 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 X Y A H vs the longitudinal conductivity σ X X 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.