Influence of Annealing Temperatures on the Structural Behaviour and Electrical Properties of La(FeSi)13 Alloys

This paper explains the effect of structural behaviour and electrical properties of cubic NaZn13-type La(FeSi)13 compounds annealed at different high temperatures from 1000ºC to 1200ºC. The Raman spectroscopy measurement revealed a different level of coexistence of La(FeSi)13-type phase and α-Fe in 1000ºC, 1100ºC and 1200ºC annealed samples. The different level coexistence of the phases suggested that the samples show a significant phase change with different annealing temperature. This finding has also supported by impedance analyzer measurement, where the pattern shows that the 1000ºC and 1100ºC samples have similar behaviour waveform pattern compared to the 1200ºC. Also, the impedance pattern clearly shows that the propagation of the signal for the 1000ºC and 1100ºC before it arrives in the conductor state (R=0.00) has high resistive values compared to 1200ºC annealed samples. Further investigation on the electrical properties were done with the conductivity and tan delta measurements. The results show that 1200ºC annealed samples have a high value of conductivity (S=18µ S/m) compared with 1100ºC (S= 0.1µ S/m) and 1000ºC (S=4.89n S/m). The tan delta measurements found that samples annealed at 1200ºC temperature has low value of resistivity (tan ɗ = 0.117) compared with 1100ºC (tan ɗ = 0.335) and 1000ºC (tan ɗ = 0.482) respectively.