Ferron-like states in YBa_2Cu_3O_(6+x)
  With the use of the Hubbard model bound hole states in YBa_2Cu_3O_(6+x) are studied. For the parameters of this crystal the exchange interaction between the spin-carrying chain ion O^- and Cu-O plane sites is shown to ensure the formation of a large ferromagnetically ordered clusters around holes in the plane. 
P.Rubin and A.Sherman (Institute of Physics, University of Tartu)