In this work, the temperature and frequency dependences of the real part of the admittance [r(f, T)] of annealed nanocomposite films containing Co 45 Fe 45 Zr 10 -based nanoparticles covered with native oxides and embedded in a doped PbZrTiO 3 ferroelectric matrix were studied. The nanocomposites studied were deposited by ion sputtering a complex target in a mixed Ar/O 2 atmosphere followed by a 15-min annealing process (with steps of 25 K) in air in the temperature range of 398 K £ T a £ 573 K. The r(f, T) of the annealed samples was measured in the temperature range of 77 K < T p < 373 K at frequencies of 50 Hz < f < 1 MHz. The observed r(f, T) dependences confirmed that the annealed samples displayed the effects of negative capacitance over the whole frequency and temperature ranges studied because of the pronounced oxidation of the nanoparticles. The r(f, T) dependences obtained are described using an earlier-developed AC hopping conductance model. Comparisons between experimental and simulation results allow the model parameters to be estimated, such as the activation energies of the hopping conductance and the lifetimes of the electrons in the nanoparticles.

The paper presents results of testing electric properties (resistance, capacity and phase angle in an equivalent parallel circuit) of ferromagnetic alloy-dielectric nanocomposites (FeCoZr) x (PZT) (100Àx) produced by ion-beam sputtering in vacuum conditions. The measurements have been performed using alternating current within the frequency range of 50 Hze1 MHz for measuring temperatures ranging from 77 K to 373 K. In nanocomposites (CoFeZr) x (PZT) (100Àx) , produced by ion beam sputtering using a beam of combined argon and oxygen ions, for x approaching the percolation threshold, frequency dependences of the phase angle 4 that resemble those occurring in RLC parallel circuits have been observed. In the low frequency area, the phase angle of 90 4 < 0 occurs. It corresponds to the capacitive type of conduction. In the high frequency area, the inductive type of conduction with 0 4 90 occurs. At the resonance frequency f 0 , characterized by the phase angle of 4 ¼ 0 , the capacity value reaches its strong local minimum. A theoretical basis for a model of the AC hopping conduction for metal-dielectric nanocomposites has been developed and on that basis frequency dependences of the phase angle, resistance and capacitive current density components have been analyzed. The obtained theoretical and experimental results have been compared.

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The use of thermal and non-thermal atmospheric pressure plasma to solve problems related to agriculture and biomedicine is the focus of this paper. Plasma in thermal equilibrium is used where heat is required. In agriculture, it is used to treat soil and land contaminated by the products of biomass, plastics, post-hospital and pharmaceutical waste combustion, and also by ecological phenomena that have recently been observed, such as droughts, floods and storms, leading to environmental pollution. In biomedical applications, thermal plasma is used in so-called indirect living tissue treatment. The sources of thermal plasma are arcs, plasma torches and microwave plasma reactors. In turn, atmospheric pressure cold (non-thermal) plasma is applied in agriculture and biomedicine where heat adversely affects technological processes. The thermodynamic imbalance of cold plasma makes it suitable for organic syntheses due its low power requirements and the possibility of conducting chemical reactions in gas at relatively low and close to ambient temperatures. It is also suitable in the treatment of living tissues and sterilisation of medical instruments made of materials that are non-resistant to high temperatures. Non-thermal and non-equilibrium discharges at atmospheric pressure that include dielectric barrier discharges (DBDs) and atmospheric pressure plasma jets (APPJs), as well as gliding arc (GAD), can be the source of cold plasma. This paper presents an overview of agriculture and soil protection problems and biomedical and health protection problems that can be solved with the aid of plasma produced with electrical discharges. In particular, agricultural processes related to water, sewage purification with ozone and with advanced oxidation processes, as well as those related to contaminated soil treatment and pest control, are presented. Among the biomedical applications of cold plasma, its antibacterial activity, wound healing, cancer treatment and dental problems are briefly discussed.

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