MAGNETIC AND TRANSPORT-PROPERTIES OF CA(1-X)LN(X)MNO(3) (LN=LA, EU ORLU)

The magnetization and transport properties of Ca(1-x)Ln(x)MnO(3) (Ln = La, Eu or Lu; 0 less than or equal to x less than or equal to 0.3) pe rovskites have been studied. It is shown that the substitution of Ca2 by La Eu or Lu up to x = 0.1 leads to a sharp increase in the magneti zation and conductivity. Further replacement of Ca results in a decrea se in the magnetization due to the regular arrangement of Mn3+ and Mn4 + ions in the ratio 1:3. The samples with 0 less than or equal to x le ss than or equal to 0.2 show metamagnetic behaviour which might result from a collapse of the charge-ordered (1:3) state. The samples with x = 0.1 and x = 0.15 exhibit a resistance variation up to 500% with H = 12 T.