SYSTEMATIC STUDIES ON SUBSTITUTIONAL EFFECTS IN LAYERED MANGANOCUPRATE EU3BA2MN2CU2O12

The stabilization of the Ln(3)Ba(2)Mn(2)Cu(2)O(12) structure as a func tion of the constituent lanthanides has been investigated. Single phas e Ln(3)Ba(2)Mn(2)Cu(2)O(12) compounds have been formed with Ln = Sm, E u, and Gd. The substitutions of other Ln ions are unsuccessful. The gr ound state changes from a spin glass to a ferromagnetic phase with dec reasing size of the Ln ion (Sm --> Gd). In order to dope holes, Ca is substituted for Eu and Sc for Mn, (Eu3-xCax)Ba-2(Mn2-yScy)Cu2O12. For x less than or equal to 0.7 (y = 0), x less than or equal to 0.5 (y = 0.5), and x less than or equal to 0.1 (y = 1.0), single phase compound s have been obtained. All the pure compounds show a semiconducting R-T behavior.