Static critical exponents at structural phase Transitions

The temperature dependence of the rotational displacement parameters below the second-order phase transitions in SrTiO3 and LaAlO3 at Ta=105.5 and 797°K is described by an exponent =0.330.02 down to t=TTa=0.95. For smaller t's there occurs a change to Landau behavior approximately followed between t=0.9 and 0.7. The observation of static critical exponents near displacive phase transitions confirms now the notion of universality in this field. © 1971 The American Physical Society.