Temperature and bias dependence of dynamic conductance—low resistive magnetic tunnel junctions

$\mathrm{I–V}$ curves of magnetic tunnel junctions were measured in a temperature range of 5–305 K. Effective barrier parameters were estimated by fitting the dynamical conductance $\mathrm{G(V)}$ with the Brinkman–Dynes–Rowell model and fitting the temperature dependence of zero-bias conductance $\mathrm{G(T)}$ with the Stratton model. A large discrepancy was discovered when comparing barrier parameters predicted by the two models. The inconsistency between the models can be explained by the presence of an inelastic, spin-independent conductance that is strongly dependent on both temperature and voltage as described by Glazman–Matveev theory of electron hopping. This additional hopping conductance helps explain the observed temperature dependence and bias dependence of magnetic tunnel junction conductance.