Effect of Iron Oxide on the Structure, Electrical and Magnetic Properties of (70% mole V_2O_5- (15-x)% mole P_2O_5-15% mole B_2O_3) Semi Conducting Glass System

摘要

A glass system according to the molar formula (70% mole V_2O_5- (15-x)% mole P_2O_5-15% mole B_2O_3), where x = 0, 1, 2.5, 5 and 7.5 % mole Fe_2O_3, was prepared by melting the pure powder chemicals at porcelain crucibles at 1000℃ for three hours until the homogenous glass was obtained. The samples were quenched in air and heat-treated at 500℃ for 1, 2 and 3 h. The density, the molar volume, the electrical conductivity and magnetic properties were measured before and after the heat-treatment. The crystalline phases due to heat-treatment were determined using x-ray diffraction. The heat-treatment causes change of BO_3 to BO_4 and forming non-bridging oxygen. Replacing the phosphorus oxide with the iron oxide increases the magnetic properties while the conductivity increase up to 5% mole and then decreases. The changes of electrical and magnetic properties with heat-treatment time have a random behavior due to the change of the structure if the samples with heat treatment.