It is predicted from ballistic quantum transport theory that the Curie temperature (Tc) of a resonant tunneling diode (RTD) with a dilute ferromagnetic semiconductor (DFS) well should switch with increasing voltage from its equilibrium value to nearly zero in two steps. Here, we consider theoretically the effect of scattering in this system within the Buttiker probe picture. An RTD can operate in three regimes: coherent, sequential, or, no resonance - in order of increasing scattering strength. In the coherent regime the broadening of the resonance due to scattering is much lesser than the 'coherent broadening' - that due to the barriers as shown in Fig. 1. In the sequential regime, the broadening due to scattering is greater than the coherent broadening, while in the third regime it is large enough to destroy the resonance altogether. Fig. 2 and 3 show the corresponding Tc-V and I-V plots, respectively. The two steps in the Tc-V get smoothed out as scattering increases - being sharp in the coherent regime, rounded but discernible in the second and non-existent in the third. The relative robustness of the second transition is shown to arise from the asymmetry in the barriers at non-zero bias. The decrease in the equilibrium Tc with scattering follows from the broadening of the DOS shown in Fig. 4 that moves more of it outside the range of filled states, leading to a decrease of the spin susceptibility. Mapping the scattering to a bulk mobility, we show that the magnetization switching effect should be observable for typical scattering rates.

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