NMR-STUDY OF THE SM2FE17 HYDRIDES

The Sm-147 NMR spin echo spectra of the Sm2Fe17Hx (x = 0, 2.9, 4.6) se ries at 4.2 K are presented. The observed quadrupole septets are assig ned to the samarium 6c site with different numbers of neighbouring hyd rogen atoms occupying the 9e and 18g interstitial sites. A significant influence of hydrogen at 18g sites on the electric field gradient is observed, but hydrogen at the 9e sites has little effect. The differen ce is discussed in terms of the distances between samarium and hydroge n 9e and 18g atoms in the structure. A relation of the corresponding e lectric field gradient to the Sm contribution to the magnetocrystallin e anisotropy is given.