Acceptor doped mixed oxides

Acceptor doping in perovskite oxides gives materials with a vacancy population that can act as proton conductors in moist atmospheres (Section 6.9). In addition, the doped materials are generally p-type semiconductors. This means that in moist atmospheres there is the possibility of mixed conductivity involving three charge carriers (H+, O2-, and h ) or four if electrons, e, are included. 

Acceptor-doped SrCe03 is, without doubt, the mixed electron-proton conducting oxide system most studied, both with respect to actual measurements of... 

Another important elass of ternary oxides with mixed ionic-electronic conductivity is based on the pyroehlore system, AjBjO,. Especially, Tuller and co-workers have studied the defect chemistry of nominally pure, and donor- and acceptor-doped GdjTijO, (GT). They have demonstrated that mixed ionic and electronic conductivity can be controlled over wide limits in the pyroehlore oxides described by compositions Gd2(Ti, xZrx)207 (GZT) and Y2(Ti,, rj207 (YZT) by control of both the parameter x and by doping. If GT is doped with Ca or by selecting x > 0.4 in GZT, an excellent solid electrolyte is obtained. Reduced or donor-doped GT exhibits predominantly a Poj-dependent semiconducting behavior. ... 

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