Magnetic properties and potential barrier between crystallites model of MgGa2-xFexO4 ceramics

• Main Authors: V. A. dos S. Ribeiro, R. M. Rubinger, A. F. Oliveira, C. S. P. Mendonça, M. R. da Silva
• Format: Article
• Language: English
• Published: Associação Brasileira de Cerâmica
• Series: Cerâmica
• Subjects: espinélio; propriedades magnéticas; barreira de potencial
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132016000400365&lng=en&tlng=en

Abstract The aim of this work was to investigate the magnetic properties and the electrical conductivity temperature dependence associated to the potential barrier between the crystallites model. Gallium and magnesium containing spinel ceramic has low magnetic coercivity and high electrical resistivity. MgGa2-xFexO4 samples (x= 0.01, 0.05, 0.15, 0.25, 0.35) were prepared by solid-state method and sintered at 800 °C for 8 h. X-ray diffraction analysis confirmed the formation of a single phase with compact cubic spinel structure. The magnetic measurements show that the saturation magnetization and remanence of all samples increased with increasing iron concentration. The coercive field decreased up to the concentration x= 0.15, and above x= 0.25 it was observed an increase in the coercive field. Through electrical characterization it was found that the samples presented highly insulating behavior for x= 0.01, and further increase in x above 0.15 gives a semiconductor behavior compatible with the potential barrier between the crystallites model, i.e. fulfills the condition L/2 > LD (crystallite size L in comparison with the Debye length LD), and the conduction is limited by potential barriers between the crystallites.