Ion-irradiation-induced amorphization of La2Zr2O7 pyrochlore

The isometric pyrochlore structure, A2B2O7, is generally susceptible to radiation damage, but certain compositions are remarkably resistant to radiation damage. In the binary system Gd2(Ti2-xZrx)O7, the radiation resistance increases dramatically with the substitution of Zr for Ti, until the pure end member Gd2Zr2O7 cannot be amorphized, even at doses as high as ∼100 dpa. Although zirconate pyrochlores are generally considered to be radiation resistant, we report results for the amorphization of a zirconate pyrochlore La2Zr2O7 by ion beam irradiation (∼5.5 dpa at room temperature). The critical amorphization temperature Tc is low, ∼310 K. The susceptibility to ion-beam-induced amorphization and structural disordering for zirconate pyrochlores is related to the structural deviation from the ideal fluorite structure, as reflected by the x parameter of the O48f