Eu2CuO4: An anisotropic Van Vleck paramagnet.

Magnetic susceptibility measurements have shown anisotropic Van Vleck paramagnetism in Eu2CuO4 single crystals. This behavior is associated with the singlet ground state (7F0) of Eu3+ ions, and the measured anisotropy is related to a crystal-field splitting of the excited multiplets (7FJ). From the experimental data at low temperatures (T50 K) a crystal-field parameter A20r2=-93(5) cm-1 and a spin-orbit coupling constant =303(15) cm-1 have been estimated. The temperature dependence of the magnetic susceptibility is predicted in terms of the Boltzmann population of the excited multiplets, and a comparison with experimental data up to 350 K is made. The possibility of a magnetic contribution arising from the Cu ions is discussed in connection with some discrepancies observed between the experimental and calculated magnetic susceptibilities. © 1989 The American Physical Society