Critical behaviour of [110]-stressed rbcaf3

We have investigated the cubic to tetragonal phase transition in RbCaF3 under [110] uniaxial stress by monitoring the EPR lines of the cubic Gd3+ centre which shift proportionaly to the square of the order parameter (the rotational anngle of the CaF6 octahedra φ) or those of the Gd3+-O2-pair which splits linearly in φ. © 1991, Taylor & Francis Group, LLC. All rights reserved.