An EPR study of Mn2+ centers in the incommensurate phase of rubidium tetrac
hlorozincate crystals is reported. It is shown that the temperature depende
nce of the high-field hyperfine line group M-S = 3/2<->5/2 can be described
in terms of a simple "local'' model.(1) The data obtained support the nonc
lassical type of critical behavior in Rb2ZnCl4 crystals corresponding to th
e three-dimensional Heisenberg model for a two-component order parameter. (
C) 1999 American Institute of Physics. [S1063-7834(99)02704-5].