High-pressure synthesis and magnetic properties of Bi0.5D0.5MnO3 (D = Pb, Ba) solid solutions

Perovskites Bi0.5D0.5MnO3 (D = Pb, Ba) were prepared under high pressure (4 GPa) at 1200-1300degreesC. According to the X-ray diffraction data, crystalline Bi0.5Pb0.5MnO3 has a tetragonal unit cell with the parameters a = 3.940 Angstrom and c = 3.800 Angstrom, whereas Bi0.5Ba0.5MnO3 crystals are cubic with a = 3.940 Angstrom. It is concluded from magnetic studies that lead-containing manganite is an antiferromagnet with T-N = 120 K, whereas Bi0.5Ba0.5MnO3 is a spin glass with spin-freezing temperature T-f = 38 K. Both compounds are decomposed upon heating in air at temperatures above 500degreesC. With the use of synthesis in air, Bi0.5Ca0.5 - xDxMnO3 solid solutions with x as high as 0.25 were obtained. (C) 2004 MAIK "Nauka/Interperiodica".