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D. Bochenek, P. Niemiec, R. Zachariasz, A. Chrobak and G. Ziółkowski

Abstract

A ferroelectric-ferromagnetic composites based on PZT powder have been obtained in presented work. The main aim of combination of ferroelectric and magnetic powders was to obtain material showing both electric and magnetic properties. Ferroelectric ceramic powder (in amount of 90%) was based on the doped PZT type solid solution while magnetic component of the composite was nickel-zinc ferrite Ni1-x ZnxFe2O4 (in amount of 10%). The synthesis of components of ferroelectric-ferromagnetic composite was performed using the solid phase sintering. Final densification of synthesized powder has been done using free sintering. For obtained of ferroelectric-ferromagnetic composites the XRD, the microstructure, EDS, dielectric, magnetic, internal friction and electrical hysteresis loop investigations were performed. Obtained results shown the correlations between the magnetic subsystem and the electrical subsystem of the ferroelectric-ferromagnetic composites. Such properties of obtained composites give the possibility to use them in memory applications of new type.

Open access

P. Wlodarczyk, L. Hawelek, P. Zackiewicz, M. Kaminska, A. Chrobak and A. Kolano-Burian

Abstract

The magnetocaloric effect in the MnxFe2−xP1−yGey intermetallic compounds with the amount of Mn in the range of x = 1.05 to 1.17 and amount of Ge in the range of y = 0.19 to 0.22 has been studied. It was found that a higher Ge/P ratio causes an increase in Curie temperature, magnetocaloric effect at low field (up to 1 T), activation energy of structural transition and a decrease in thermal hysteresis, as well as transition enthalpy. Contrary to this observation, higher Mn/Fe ratio causes a decrease in Curie temperature, slight decrease of magnetocaloric effect at low magnetic field, and an increase in thermal hysteresis. Simultaneous increase of both ratios may be very advantageous, as the thermal hysteresis can be lowered and magnetocaloric effect can be enhanced without changing the Curie temperature. Some hints about optimization of the composition for applications at low magnetic fields (0.5 T to 2 T) have been presented.

Open access

M. Kizerwetter-Świda, D. Chrobak-Chmiel, M. Rzewuska, A. Antosiewicz, B. Dolka, A. Ledwoń, A. Czujkowska and M. Binek

Abstract

Coagulase-positive staphylococci (CoPS) are opportunistic veterinary pathogens, of which Staphylococcus aureus, S. delphini and S. intermedius can be isolated from pigeons. The biochemical identification of S. delphini and S. intermedius isolates may be incorrect, because of their phenotypic similarity. The purpose of the present study was to isolate and identify CoPS from domestic and feral pigeons and to determine their genetic relatedness by PFGE. A total number of 31 isolates of CoPS were obtained, 15 were identified as S. delphini group B, six as S. aureus, four as S. delphini group A, three as S. intermedius and three as S. schleiferi subsp. coagulans. The results indicate that S. delphini group B is the predominant CoPS species among pigeons studied. PFGE restriction patterns of S. delphini group A and S. delphini group B form separate clusters, demonstrating their genetic heterogeneity. Indistinguishable or very similar PFGE patterns observed among S. delphini group B isolates from domestic and feral pigeons confirm the possibility of CoPS transmission between these birds.