Ions Substitution Effect On The Magnetic Phase Transition Temperature Of 0.5bifeo(3)-0.5pb(1-X)Sr(X)Tio(3) Multiferroic Solid Solutions

0.5BiFeO(3)-0.5Pb(1-x)Sr(x)TiO(3) (0 <= x <= 1) solid solution compositions were synthesized using solid phase reactions route from high-purity oxides. Mossbauer studies showed that for 0.5BiFeO(3)-0.5PbTiO(3) (x = 0) the magnetic phase transition temperature T (M) value was about 130 K. Substitution of Sr for Pb led to a dramatic decrease in T (M), though the Fe content did not change with x and for 0.5BiFeO(3)-0.5SrTiO(3) (x = 1) T (M) was only approximate to 20 K. This dramatic difference in T (M) values seems to be due to additional contribution of the magnetic superexchange between Fe3+ ions via the empty 6p states of Bi3+ and Pb2+ ions to the overall superexchange.