Hyperfine fields in R2CO17

Nuclear magnetic resonances of Co59 in R2Co17 (R=Ce, Pr, Gd, Tb, Dy, Ho) are observed at liquid N2 temperature. Hyperfine fields of Co59 are estimated using Hsub(Co)=(a+b Nsub(Co))μsub(Co)+cNsub(R)μsub(R)(S) and compared experimentally, where a=-30.4 kOe/μsub(B), b=-7.8 kOe/μsub(B), Nsub(Co) and Nsub(R) are number of Co and R neighbors, respectively, and μsub(Co) and μsub(R)(S) are magnetic moments of Co and R spins, respectively. Magnetic moments of R2Co17 are also calculated, based on NMR observations, and shown to be in agreement with magnetic measurement data. It is pointed out that the Co magnetic moment surrounded locally by only cobalt atoms will be different from that of the other cobalt sites. (auth.)