Multi-ferrous composite materials, power, electricity, magnetic coupling mechanism and properties

　　Title: Multi-ferrous composite materials, power, electricity, magnetic coupling mechanism and properties of
　　Author: Lu Xiaoyan
　　Degree-granting unit: Harbin Institute of Technology
　　Keywords: complex multiple-ferrous;; Ginzburg-Landau theory;; dielectric constant;; bending properties;; energy release density
　　Abstract:
　　Multi-iron material is a class of ferroelectric, ferromagnetic and ferroelastic coupling between the two or more properties of both materials, this material
　　Under external electric field can induce magnetic polarization, the outer magnetic field can induce electric polarization, with the effect of Neodymium Magnets magnetic coupling product performance. This strange
　　Special performance for the materials and devices designed to increase the degree of freedom, in a multi-site information storage and read-write, wireless microwave devices, wireless sensor networks
　　Network and multi-functional electronic devices have great potential applications, has become a hot research field of functional materials.
　　With multiple Railway of
　　Single type of substance and material in nature, very few, and most at very low temperatures have a strong magnetic coupling effect, and the use of ferroelectric
　　Scalability and electroluminescent materials the magnetostriction of the magnetic elastic coupling through the interface between the compound prepared in multi-material iron
　　Room temperature with a large magnetic coupling. Because of this magnetic coupling mainly from the elastic coupling between the two phases, and therefore, analysis of two
　　Phase interface between the film and substrate interface interaction between the elastic carefully consider the external electric field and external magnetic field on the stress field within the material
　　Influence each other in order to match a reasonable choice of material, greater magnetic coupling properties. In this paper, a composite http://www.everbeenmagnet.com/en/products/110-sintered-neodymium-magnets of multiple materials of iron
　　Coupling mechanism, detailed consideration of the size effect, surface effect, volume copies, thickness, and a variety of stress and strain on the material properties,
　　Also concerned about how to use some of the features of this coupling performance structural materials to achieve more than many degrees of freedom control, and finally, the fracture of materials
　　Done a preliminary analysis of the performance. The following are the main research paper ideas, methods and conclusions:
　　1) Based on Landau theory, detailed
　　Analysis of the 1-3 type ferroelectric ferromagnetic nano-composite materials in a variety of stress-strain relationship and interaction between the free energy of the system
　　. Include a variety of stress-strain ferroelectric phase electrostrictive strain and strain and magnetostriction ferromagnetic phase between the two phases and films and linings
　　Since the end of the lattice mismatch between the mismatch stress and dislocation resulting from the release because the stress between the elastic interaction. The establishment of the electrode
　　And magnetic polarization of the time evolution of the Ginzburg - Landau equation dynamics, bifurcation theory predicted by two-phase materials, the phase transition point, the use of numerical
　　Method gives the steady state polarization and magnetic pole strength of the two phases of strength and strain state, and based on the Landau-Khalatnikor side
　　Method, numerical simulation of the coupling field intensity under the electrode and pole of the intensity of the butterfly curve;
　　2) based on Ginzburg-Landau
　　Elasticity theory with Timeshenko method of dielectric / magnetic alloy (Ba0.6Sr0.4TiO3/terfenol-D) layered composites
　　Dielectric properties studied. The use of an external magnetic field-induced magnetic alloy magnetostriction can be adjusted within a certain range of small barium strontium titanate
　　Field dielectric properties, and by changing the Ba / Sr composition ratio and thickness greater than can be achieved within the scope of regulation;
　　3) the use of magnetic coupling
　　Effect, the design of ferroelectric / ferromagnetic layered bent-type drive, and use the method of Hsueh ferroelectric / magnetic alloy laminated composite curved
　　Performance studies. The results show that the magnetic field control terfenol-D magnetostrictive layer can control the vertical structure of the relative bending
　　Move up to 55%;
　　4) energy-based approach, from a macro-scale study of ferromagnetic ferroelectric fiber reinforced matrix composite knot
　　Structure of the fracture toughness. Consider the power, electricity and magnetism more than the magnetic coupling effect of the performance obtained on the ferroelectric polarization and magnetic pole of strength
　　Intensity of energy release density function. Structure is heavily dependent on the fracture toughness of ferroelectric materials and the size of the polarization of ferromagnetic materials, two
　　Phase composition and interface flexibility than the interaction.
　　Degree Year: 2009