A different kind of multiferroics with ferroelectric-ferrimagnetic (FE-FM) composites: (1 -x) PbZr 0.53 Ti 0.47 O 3 -x Ni 0.65 Zn 0.35 Fe 2 O 4 with x = 0.10, 0.20 and 0.30, were synthesized by a powder-in-sol precursor hybrid processing route. Structural analysis with X-ray diffraction (XRD) data revealed the presence of both PbZr 0.53 Ti 0.47 O 3 (PZT) and Ni 0.65 Zn 0.35 Fe 2 O 4 (NZFO) pure phases in the PZT-NZFO composites. Scanning electron micrographs (SEM) clearly disclose distribution of both PZT and NZFO phases throughout the sample.Dielectric and electrical properties of the system have been investigated in a wide range of frequency at different temperatures. Dielectric constant (e r ) as a function of temperature reveals the paraelectric-FE transition temperature at *408°C having maximum value of e r at the peak [e r max = 1,200] with another low temperature anomaly at *297°C, very close to the magnetic Curie temperature of the NZFO ferrite (T c = 300°C) for the x = 0.1 FE-FM composite. The impedance spectroscopy data of these composites show clearly, contribution of both grain and grain boundary effect in the electrical properties of the composites. Negative temperature coefficient of resistance (NTCR) behavior of the materials indicates their semiconducting nature. The ac conductivity spectrum is found to obey Johnscher's power law very well. The temperaturedependent magnetization hysteresis (M-H) loops of the PZT/NZFO composite show excellent non-saturating ferrimagnetic behavior with increase in both coercive field (H c ) and remanent magnetization (M r ) when the NZFO content in the composite is increased. Polarization (P) versus electric field (E) studies at 300 K give conclusive evidence of the presence of spontaneous polarization in all the three composites (x = 0.1, 0.2 and 0.3). However, area of P-E loop, coercive field (E c ) and remanent polarization (P r ) are found to decrease noticeably with the increase of the NZFO content (x) in these composites.
When two surfaces touch each other, intimate contacts occur at the tips of the asperities and adhesional interaction between the solids arising out of the surface forces becomes significant. This effect need be considered in MEMs, micro-machines, magnetic storage systems other such situations where the surfaces are inherently smooth and loads are extremely low. Surfaces in these and many other tribological contacts may have sub-micron or even nanometric levels and the stochastic model for rough surfaces that typically applies to engineering surfaces is not suitable. The rough surface model is these circumstances must cover asperities ranging from nanometer to micrometer level and this essentially needs a fractal approach. The paper describes a theoretical study of adhesive wear at the contact between surfaces with nanometric level asperities at low loads using a fractal contact model and taking into account the surface forces. The model predicts wear between solids with wide range of material and surface properties. The results broadly confirm the experimental observation such as dependence of wear volume on normal load and also on adhesion due surface forces. Furthermore the fractal analysis gives a generalized solution and depending on the combinations of material and fractal parameters specific solutions, relevant to realistic situations may be arrived at, are obtained. Under certain parametric combinations high wear even under tensile load is predicted while near zero wear is expected for some another set of parameters. These predictions are certainly advantageous in the selection of surface and material properties in applications where loads are small and surfaces are ultra smooth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.