NOTE ON THE CRYSTAL-FIELD AND INTERSUBLATTICE COUPLING IN ER2FE17C AND TM2FE17C STUDIED BY MEANS OF THE ER-166 AND TM-169 MOSSBAUER-EFFECT

The temperature dependence of the Er-166 and Tm-169 hyperfine fields i n Er2Fe17C and Tm2Fe17C was studied in extended temperature regions on both sides of the spin reorientation temperature. From fits of these temperature dependences we obtained values of the second-order crystal field parameter (A2(0) = -300 K a0(-2)) and the intersublattice coupl ing constants (J(ErFe)/k = -6.3 K, J(TmFe)/k = -6.0 K). The value of A 2(0) obtained in this way agrees with an earlier determination based o n the quadrupolar splitting of the Er-166 and Tm-169 Mossbauer spectra .