Paramagnetic short-range order in MnF2 beyond the critical region

Measurements of paramagnetic diffuse scattering in a single crystal of MnF2 were done in complete (h k 0) and (h 0 1) planes at the Flat-cone diffractometer E2. of the Berlin reactor. The data have been evaluated with an extended molecular field theory up to a temperature of 170 K (TN = 67.4 K). Good agreement with the experiment could be achieved by introducing a renormalized temperature as parameter. This parameter describes the transition between the critical and the molecular field region. (C) 2000 Elsevier science B.V. All rights reserved.