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

LaSr-manganate (LaSr)MnO3 with perovskite structure was prepared in the bas ic system MnO2-SrO-La2O3-B2O3(-SiO2) by a modified glass crystallization me thod. X-ray diffraction, magnetic measurements, EDX and particle size inves tigations (specific surface) were carried out. The influence of the anneali ng conditions on the phase composition and the magnetic properties of the p owders are discussed. In the silicate-free system manganate powder samples show values of specific saturation magnetization up to 53 Am-2/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 sy stem the borate phase was leached out to act a manganate-SiO2 mixture which could be sintered to bulk samples. The sintering conditions have been vari ed to avoid a decrease of the magnetization due to the formation of non-mag netic phases. Sintered samples show a superposition of the CMR and the GMR effect due to grain boundaries. (C) 2001 Elsevier Science Ltd. All rights r eserved.