Study of electromagnetic properties for the Ba2FeReO6 versus Ca2FeReO6 double perovskites in microwave range: Simulational analysis

A pair of Re-based double perovskites, A₂BB´O₆ have been analyzed in this paper, presenting ferrimagnetic properties but different characteristics, the Ba₂FeReO₆ being a metal and the Ca₂FeReO₆ an insulator above the transition temperature to the ferrimagnetic state. The study was performed at 10 GHz in microwave range and the thermal evolution of the electromagnetic parameters of the two materials was determined by structural simulation methods. The curves of the magnetic permeability and electrical conductivity versus temperature were given for the temperature domain of 300 ÷ 700 K. The ferrimagnetic transition generates a peak on the permeability curves, determined by the material response to the field and a step in resistivity evolution, caused by the changing of the internal order over the transition to ferrimagnetic state. Different physical state of the materials (metal/semiconductor/insulator) imposes the thermal characteristics shape and the threshold values.