Tuning the structural instability of SrTiO3 by Eu doping: The phase diagram of Sr1-xEuxTiO3

The phase diagram of Sr1-xEuxTiO3 is determined experimentally by electron paramagnetic resonance and resistivity measurements and analyzed theoretically within the self-consistent phonon approximation as a function of x (0.03 <= x <= 1.0). The transition temperature of the structural instability of the system increases nonlinearly to higher temperatures with increasing x. This is interpreted theoretically by a substantial alteration in the dynamics caused by a change in the double-well potential from broad and shallow to narrow and deep.