Study of dielectric function of (FeCoZr)x(CaF2)(100−x) nanocomposites produced with a beam of argon ions

The paper presents investigations of frequency and temperature dependences on capacitance, phase shift and loss tangent of nanocomposites (FeCoZr)x(CaF2)(100−x) of the metallic phase content x = 66.3 at.%. The sample was subjected to 15 min annealing at temperature 723 K. It has been established that within the range of 50 Hz-5 × 104 Hz the frequency dependence on capacitance and conductivity is weak. Further frequency increase brings about rapid decrease of capacitance and the conductivity growth. Those both processes can be described with the same relaxation time value of ca 5 × 10−7 s. Based on the Arrhenius plots, activation energy values have been determined and they are of ca 0.112 eV and 0.0134 eV for the conductivity and permittivity, respectively. It is consistent with the model of hopping recharging, which shows that the permittivity activation energy should be lower than the conductivity activation energy. It has been established, that order of the permittivity activation energy is comparable to the potential energy of the interaction between elementary charges, negative and positive (dipole) ones located in adjacent potential wells.