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Magnesium doping on brownmillerite Ca2FeAlO5
Malveiro, J.; Ramos, T.; Ferreira, L. P.; Waerenborgh, J. C.; Nunes, M. R.; Godinho, M.; Carvalho, M. D.Ca2FeAl1-xMgxO5 (x=0, 0.05 and 0.1) compounds adopting the brownmillerite-type structure were prepared by a self-combustion route using two different fuels. Characterisation was performed using X-ray powder diffraction, Mössbauer spectroscopy, magnetisation measurements, chemical analysis, scanning electron microscopy and 4-point dc conductivity measurements. Global results indicate that the solubility limit wa...
Structural and Magnetic Characterization of the Series La1-xSrxFe0.8Cr0.2O3-δ (...
Ramos, T.; Carvalho, M. D.; Ferreira, L. P.; Cruz, M. M.; Godinho, M.A series of perovskite compounds with the general formula La1-xSrxFe0.8Cr0.2O3-δ (x = 0.2, 0.4, 0.6, and 0.8) have been synthesized using a urea/nitrates self-combustion route. Their characterization was performed using room-temperature X-ray diffraction, electrical and magnetization measurements. A structural transition from orthorhombic (x = 0.2) to rhombohedral (x > 0.2) was determined. Among the rhombohedra...
Morte de plântulas de soja provocada pelo excesso de umidade e falta de aeração...
TORRES, E.; ALMEIDA, A. M. R.; SARAIVA, O. F.; HENNING, A. A.; FRANCHINI, J. C.; GALERANI, P. R.; FERREIRA, L. P.O presente trabalho, de caráter exploratório, foi motivado pelo fato de que nas últimas safras agrícolas, em muitas áreas cultivadas com soja, ocorreu um alto índice de mortalidade de plântulas de soja, que inicialmente apresentavam lesão na extremidade da raiz principal, seguida por infecção causada por fungos normalmente encontrados no solo. Em avaliações preliminares, constatou-se que a maior incidência de m...
Study of RFe12−xMox (R =Y, Ho) compounds by neutron powder diffraction, ac susc...
Campos, J. Ayres de; Ferreira, L. P.; Cruz, M. M.; Gil, J. M.; Mendes, P. J.; Ferreira, I. C.; Bacmann, M.; Soubeyroux, J.-L.; Fruchart, D.; Godinho, M.Neutron powder diffraction, magnetization and ac susceptibility measurements were performed on compounds of the series RFe12−xMox (R D Y and Ho, x D 1, 2, 3). The influence of the Mo content on both structural and magnetic properties is discussed. Comparison with published data for different Mo concentrations is made. It is found that the effect of Mo substitution for Fe on structural and magnetic properties ca...
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