Crystal-field, exchange interactions and magnetism in pyrochlore ferromagnet R2V2O7 (R3+=Y, Lu)

► R2V2O7 has easy-axis single-ion anisotropy when ferromagnetic clusters lie in the paramagnetic phase. ► Variation of electronic and magnetic properties linked to their structural parameters. ► Removal of degeneracy and splitting of ground doublet initiates FM clusters at ∼170 K.