GeTe has attracted extensive attention due to high thermoelectric performance. Herein, we comprehensively investigate the effect of rare earth element (Eu, Gd, Er and Tm) substitutions at Ge site on its It is found that substitution limit Eu, Tm increases from 0.8 1.8 mol.% with increasing atomic number. The local magnetic moment arising substituted enhances Seebeck coefficient in turn results ...