Stark and Zeeman effects in Nd2Fe14B and Pr2Fe14B intermetallics

The energy level scheme of the Nd3+ and Pr3+ ions in ferromagnetic Nd2Fe14B and Pr2Fe14B intermetallic compounds was evaluated on the basis of all known experiments. In calculations the effect of charge (Stark effect) and spill-dependent (Zeeman effect) interactions were taken into account by means of the crystal-field and molecular-field approximation, respectively. The derived energy level scheme is associated with the removal of the degeneracy of the lowest multiplet given by Hund's rules, i.e. I-4(9/2) (Nd3+) and H-3(4) (Pr3+). The revealed low-energy electronic structure <25 meV = 200 cm(-1) is associated with many-electron states of the RE(3+) ions. Magnetic and electronic properties resulting from this fine structure are compared with all known experimental results. The localized crystal electric field levels exist also in Nd2CuO4, all ionic compound which by doping with Ce becomes high-T-c superconductor, indicating the formation of crystal electric field states independently on the metallic or ionic state.