LaSr-manganate powders and bulk material by crystallization of a glass

LaSr-manganate (LaSr)MnO3 with perovskite structure was prepared in the basic system MnO2–SrO–La2O3–B2O3(–SiO2) by a modified glass crystallization method. X-ray diffraction, magnetic measurements, EDX and particle size investigations (specific surface) were carried out. The influence of the annealing conditions on the phase composition and the magnetic properties of the powders are discussed. In the silicate-free system manganate powder samples show values of specific saturation magnetization up to 53 Am2/kg, a Curie temperature between 369 and 389 K and a mean particle size in the order of 100 nm. The powders reveal the magneto-resistive effect. In the silicate system the borate phase was leached out to get a manganate-SiO2 mixture which could be sintered to bulk samples. The sintering conditions have been varied to avoid a decrease of the magnetization due to the formation of non-magnetic phases. Sintered samples show a superposition of the CMR and the GMR effect due to grain boundaries.