Mechanical losses and dielectric proporties in ferroelectric-ferromagnetic composites

Radosław Zachariasz, Dariusz Bochenek, Jan Ilczuk

Quarterly No. 4, 2013 pages 250-254

DOI:

keywords: mechanical losses, internal friction, Young's modulus, ferroelectric-ferromagnetic composites, PZT-type ceramics, ferrites, multiferroics

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abstract The work presents the technology and investigation results of ferroelectric-ferromagnetic composites based on ferroelectric powders of the PZT type and ferrite. The ferroelectric powder comprised two PZT type compositions: Pb_0.84Ba_0.16(Zr_0.54Ti_0.46)O₃ + 1.0%at. Nb₂O₅ (PBZTN) and Pb(Zr_0.51Ti_0.49)O₃ + 0.2%at. Bi₂O₃ + 0.03%at. Nb₂O₅ + 0.06%at. MnO_{2 (PZTBNM). The initial constituents for obtaining the PZT type powders included oxides: PbO, ZrO2, TiO2, Nb2O5, Cr2O3 as well as carbonates: barium BaCO3 and strontium SrCO3. In the PZT-ferrite composites, the synthesized ferroelectric powder constituted 90%, whereas the ferrite powder (Ni0.64Zn0.36Fe2O4) was 10%. Temperature examinations of the internal friction (IF) of the PZT-ferrite type composites, which belong to non-destructive methods of material examination in mechanical spectrometry, and also measurements of the dielectric properties were performed. The IF method enabled the authors to determine mechanical properties such as mechanical losses or value of Young's modulus in a broad range of temperatures. For both the investigated composites, an increase in mechanical losses Q^–1 and decrease in Young's modulus Y with an increase in temperature were observed. At the phase transition point connected with an electric sub-system change while changing from the ferroelectric to paraelectric state, a rapid increase in Young's modulus Y was observed. It was confirmed in further investigations of dielectric properties (T) i tan(T).}