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Effect of BaZr <sub/>0.4</sub> Ti <sub/>0.6</sub> O <sub/>3</sub> addition on electrical and magnetic properties of multiferroic (1-x)BiFeO <sub/>3</sub> -xBaTiO <sub/>3</sub> ceramics
摘要： The 0.75((1-x)BiFeO3-xBaTiO3)-0.25BaZr0.4Ti0.6O3 or 0.75(BFO-BTO)-0.25BZT ceramics (x = 0.23–0.27) have been prepared by solid state reaction method to studied the relationship between phase formation, dielectric and magnetic properties. The results found that the phase formations of calcined BFO-BTO and BZT powders are distorted rhombohedral and cubic structure, respectively. Moreover, the addition of BZT in BFO-BTO-BZT ceramics affected to the phase change dramatically according to increasing of BZT content compared to calcined BFO-BTO powders. All the samples showed cubic perovskite structure. The room temperature dielectric properties decreased with increasing of BTO content, the highest dielectric constant with low losses observed in 0.75(0.77BFO-0.23BTO)-0.25BZT ceramic. Furthermore, the ceramics displayed maximum dielectric constant temperature (Tm) above 360 °C. Interestingly, all ceramic compositions exhibited typical ferromagnetic hysteresis loop and the highest remanent magnetization observed in 0.75(0.77BFO-0.23BTO)-0.25BZT ceramic.
关键词： composite,dielectric properties,ferromagnetic hysteresis loops,BFO-BTO,BZT
更新于2025-11-14 17:28:48
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Temperature-dependent phase transition in [001]-oriented 0.72Pb(MgNb)O-0.28PbTiO single crystals
摘要： Temperature-dependent dielectricity and polarization of [001]C-oriented 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 relaxor-based ferroelectric single crystals were studied by using a combined method of the X-ray di?raction, dielectric spectrum, polarization-electric (P-E) ?eld hysteresis loops, and the Landau-phenomenological theory. Results show that the room-temperature rhombohedral phase experiences a rhombohedral-monoclinic-tetragonal coexisting state, then transforms to tetragonal phase, and ?nally to cubic phase during the zero-?eld-heating process. The six-order Landau-type thermal expansion parameters for the tetragonal phase were determined by using the typical characteristics at the cubic-tetragonal phase transition in the temperature range from 91 °C to 113 °C. The calculated dielectric curve, polarizations, and P-E loops ?t well with the experimental results. The phase stability and piezoelectricity are further studied and compared with those of the PMN-0.36PT single crystal. The provided methods and obtained Landau parameters can be used for further studies on the relaxor-based ferroelectric single crystals.
关键词： PMN-PT single crystals,Phase transition,Double hysteresis loops,Landau expansion parameters
更新于2025-11-14 17:28:48
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Investigation of Fe-doped room temperature dilute magnetic ZnO semiconductors
摘要： Different ceramics sample of Zn1-xFexO (ZFO) series have been sintered by solid state reaction method. Single phase polycrystalline Fe-doped ZnO sample with hexagonal wurtzite structure has been obtained with x < 0.03 mol. Segregation of Fe and/or its oxides have not been found in the XRD patterns. A weak secondary phase of ZnFe2O4 has been detected with x ≥ 0.03 mol. Presence of Ohmic conductivity has been detected in the dielectric property analysis and the reasons for this Maxwell-Wagner-Sillars (MWS) relaxation has been explained by the grain boundary barrier defect (GBBD) process. The obtained shift of diamagnetic behavior of pure ZnO samples to para-magnetic for ZFO samples has been established with the defect and impurity structure. The band gap energy for ZFO samples has been calculated between 2.85 eV to 3.15 eV. The results indicate the potential use of Fe doped ZnO ceramics in high frequency device applications.
关键词： Spintronics,XRD,Hysteresis loops,Dilute magnetic semiconductor,Dielectric constant,Optical property
更新于2025-10-22 19:40:53
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Temperature-Dependent Phase Transition in Orthorhombic [011]c Pb(Mg1/3Nb2/3) O3-0.35PbTiO3 Single Crystal
摘要： Relaxor [011]c PMN-0.35PT single crystal phase transition characteristics are investigated through various methods including variable temperature dielectric properties, X-ray diffraction, bipolar ferroelectric hysteresis loops (P-E) and electric-field-induced strain (S-E) hysteresis loops measurements. The results reveal that two phase transitions exist within the range from room temperature to 250 °C: orthorhombic (O)-tetragonal (T)-cubic (C). The O-to-T and T-to-C phase transition temperatures have been identified as 84 °C and 152 °C, respectively. Diffuseness degree of the T-to-C phase transition for the unpoled single crystal has been calculated to be 1.56, implying an intermediate state between normal and relaxor ferroelectrics. Temperature-dependent remanent polarization (Pr), coercive field (Ec), saturation polarization (Ps), hysteresis loop squareness (Rsq), and longitudinal piezoelectric constant (d*33) are also explored to learn the details of the phase transitions. Variable temperature unipolar Suni-E hysteresis loops avail additional evidence for the microstructure change in the as-measured single crystal.
关键词： temperature-dependent phase transition,S-E hysteresis loops,P-E hysteresis loops,orthorhombic [011]c PMN-0.35PT,dielectric properties,piezoelectric properties
更新于2025-09-23 15:22:29
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Development and calibration of a MFM-based system for local hysteresis loops measurements
摘要： A measurement technique derived from a field-dependent magnetic force microscope (MFM) is presented for the measurement of local hysteresis loops on patterned micrometric and sub-micrometric magnetic structures. The technique exploits the synchronisation of the applied field variations with the end-of-line signal of the microscope, while keeping the slow scan axis disabled. In this way, a single MFM image contains the whole field evolution of the magnetisation processes in the sample along a user-defined profile. An analysis procedure is presented for the subsequent determination of local hysteresis loops on magnetic dots. The system has been calibrated for what concerns the applied field values. No significant artifacts induced in the measurements by the applied field have been observed up to applied fields of ≈ 1000 Oe.
关键词： patterned magnetic structures,MFM,magnetic force microscope,magnetisation processes,local hysteresis loops
更新于2025-09-09 09:28:46