Electrical and magnetodielectric coupling properties of Co-doped PMN-32PT ferroelectric single crystal
Graphical abstract
The magnetic field can control the dielectric properties of the material for Co-doped PMN-32PT single crystals, which provides additional freedom for new device design. It has broad application prospects in the development of new multifunctional devices and the realization of device miniaturization. Fig. 1 (a) The dielectric constant of Co-doped PMN-32PT crystal at room temperature changes with frequency under zero magnetic field. (b) The variation curve of magneto-dielectric coecient with frequency under different magnetic fields. (c) The curve of dielectric constant with magnetic field at the same frequency.
Introduction
In recent years, the search for single phase multiferroic materials with magnetodielectric coupling effects is a hot topic in the field of materials science [[1], [2], [3]]. Multiferroic materials with single phase have both spin ordering and spontaneous polarization sequence at certain temperature. The magnetodielectric coupling properties of single-phase multiferroic materials provide an additional degree of freedom for new device designs compared to devices with a single ferromagnetic or ferroelectric property. The electric polarization of the material can be controlled by an external magnetic field or the magnetic properties of the material can be controlled by an external electric field, which has broad application prospects for the development of new multifunctional devices and miniaturization of devices in the future [4].
At present, people prepare single-phase multiferroic materials according to the design idea of magnetodielectric composite materials, that is, the coexistence of ferroelectricity and magnetism is realized by using some magnetic ions to dope typical high-temperature ferroelectrics. For example, the literature [5] reported that in Co-doped KNbO3 ceramics, room temperature ferromagnetism was introduced while maintaining the electrical properties of the material, and it was found that the doping of Co can effectively suppress the heterophase in the material. The study [6] stated that some researchers introduced Fe into the BaTiO3 thin film and successfully prepared multiferroic materials with ferroelectric and ferromagnetic properties. However, these materials exist problems such as large leakage current and low piezoelectricity, which limit further practical application of the materials.
PMN-32PT,a typical relaxation ferroelectric crystal, has been widely studied by researchers due to its high electromechanical coupling coefficient (k33>90%), high piezoelectric constant (d33 > 2500 pC/N), high strain (1.7%), high dielectric constant (ε > 4000), and low dielectric loss (tanδ < 0.01) at morphotropic phase boundary (MPB) [7,8]. It has been reported that the doping of PMN-32PT crystals by rare earth or transition metal ions causes changes in their structural, electrical and optical properties [9,10]. However, reports on the magnetodielectric coupling effect caused by doping transition metal elements are rarely seen. Therefore, in this work, the Co-doped PMN-PT single crystal was first grown by the flux method, and its structure, dielectric, ferroelectric, piezoelectric and magnetodielectric coupling properties were systematically discussed.
Section snippets
Crystal growth
Co-doped PMN-32PT single crystal was grown by the flux method. PbO, Nb2O5, TiO2, MgO and Co2O3 with purity higher than 99.9% were selected as raw materials. Nb2O5 and MgO were firstly pre-synthesized to MgNb2O6 (MN) as precursors to avoid the formation of pyrochlore phase. Then the as-synthesized MN, TiO2 and PbO were weighed according to stoichiometric mole ratio of 68:32 and 3 wt% of Co2O3 dopant was added. Additionally, 80 wt% excess PbO was added as cosolvent and also for compensating the
Results and discussion
Several Co-doped PMN-32PT single crystals are selected for XRD analysis. Fig. 1(a) shows the XRD diffraction pattern of single crystal powder. The phase structure of the as-grown crystals was determined as pure perovskite structure without pyrochlorite phase, indicating that the Co ions diffused into the crystal lattice of the PMN–32PT single crystals and formed solid solution. Fig. 1(b) is the diffraction peak of a single crystal wafer used for electrical performance testing. Three evident
Conclusions
The Co-doped PMN-32PT ferroelectric single crystal was grown by flux method, the structure was perovskite phase. The rhombohedral-tetragonal phase transition temperature of the as-grown single crystal along [001] orientation was enhanced to 107 °C, and the dielectric constant (ε) exhibited typical relaxation behavior for temperature and frequency. The coercive field (EC) and piezoelectric constant of the [001] oriented crystal were found to be 7.91 kV/cm and 1200 pC/N, respectively. When an
Author statement
I declare that the paper submitted is my personal research work under the guidance of my supervisor. Papers do not contain published or written work by others. The contributions made by my colleagues to this research institute have been clearly described in the paper. If there are any inaccuracies in the paper, I assume all relevant responsibilities.
Declaration of competing interest
We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Electrical and magnetodielectric coupling properties of Co-doped PMN-32PT ferroelectric single crystal”.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant No. 51772235), the Shaanxi Key Laboratory Fundament Research Foundation (14JK1333) and Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices (Grant No. 2015SZSJ-59-5).
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2022, MESIICON 2022 - International Interdisciplinary Conference on Mathematics, Engineering and Science, Proceedings