“…Actually, YCo 5 has become a real workbench for the study of the 3d orbital polarization, 11,12 as well as for the ab initio calculations of MAE and orbital magnetic moment. [13][14][15][16][17][18][19][20] At the same time, taking advantage of the structural regularity of the R mþn T 5mþ3n B 2n series, the researches have extended over various stabilized stoichiometries, particularly with m ¼ 1 and n ¼ 1, 2, 3, and infinity. Thus, neutron diffraction experiments performed on R nþ1 Co 3nþ5 B 2n (n ¼ 1, 2, 3 and infinity) have brought evidence on (i) the preferential occupation character of the 3d metal sites; 21,22 (ii) the dependence of the local cobalt magnetic moments on the details of the local environment, particularly on the presence of B atoms nearest neighbors (n.n.…”