(La2/5Ba2/5Ca1/5)(Mn (2/5)-xNixTi3/5)O3: Rietveld studies, dielectric and magnetic properties of new perovskite-related oxides

Abstract

Oxides of the type (La2/5Ba2/5Ca 1/5)(Mn(2/5)-xNixTi3/5)O 3 (0 ≤ x ≤ 0·4) have been synthesized by the ceramic route. All the above oxides have been found to crystallize in the cubic perovskite structure. Rietveld refinement of the Ni-based oxide, (La 2/5Ba2/5Ca1/5)(Ni2/5Ti 3/5)O3 gave rise to a composition (La 0·44Ba0·38Ca0·18) (Ni 0·42Ti0·58)O2·85(6) and the refined lattice parameter obtained was 3·9411(2) Å (space group Pm3̄m; R(F2) = 0·026, Rp = 0·074, wRp = 0·087). A shift from antiferromagnetic to paramagnetic behaviour is observed with increase in nickel concentration, the Mn-rich phases showing antiferromagnetism around 5 K. There is a systematic decrease in the dielectric constant, ε and loss tangent with increase in Ni concentration (from ε = 592 for x = 0 to ε = 78 for x = 0·4). © Indian Academy of Sciences.