Ferroic Materials

Ferroics such as ferroelectrics, ferromagnetics, and ferroelastics are functional materials widely used in modern electronics. The development of high-level miniaturized and integrated devices requires the prediction of material properties for a given target performance. To that end, multiscale simulations have become an effective method for the discovery and design of new materials.

Objectives

  • Discovery and prediction of new material systems with specific magnetic properties
  • Predict magnetic properties and structural transformations under external loads
  • Magnetic properties and structure transformation of martensite and alloys

Methods

  • DFT calculations
  • Phase-field modeling
  • Micromagnetic simulations

Current topics

The magnetocaloric effect (MCE) has been intensively studied over the last decades and is a promising alternative to conventional gas compression cooling devices. Despite a lot of research on different material systems, there are no systematic studies on the influence of the microstructure on the MCE. We combine micromagnetic simulations with a phase field model to perform finite element simulations on first-order phase transition materials and calculate the MCE. Such simulations can help to optimize the MCE in future magnetocaloric cooling devices and increase the efficiency by microstructure and geometry optimization.

In two-dimensional (2D) systems, the long-range magnetic order is strongly suppressed by thermal fluctuations. The 2D Magnetic and the investigation of these interactions of thermal fluctuations and spin order is theoretically very important. Atomically thin, layered van der Waals (vdW) crystals are ideal 2D material systems with exceptional physical properties. Motivated by these things, The realization of long-range ferromagnetic order in 2D-vdW crystals, combined with their rich electronic and optical properties has recently attracted considerable attention. Currently, we carry out the Density Functional Theory (DFT) to investigate the Structural and Magnetic Properties of Vwd. Also, using the mapping and Four-states methods, we calculate the Heisenberg coupling for the first, the second, and the third neighbors on the strain and gradient strain.

The topological objects of functional materials have shown many novel properties, which have perspective applications in memory devices and modern sensors. In ferroics, magnetic vortices, magnetic skyrmion, and analogous structures in ferroelectric materials have attracted wide research interests all over the world. By using phase field simulations, the formation mechanism, dielectric property, electrocaloric/magnetocaloric property, mechanical properties can be investigated. The temporal evolution and dynamics of such topological structures can also be explored by applying external fields. The understandings from phase field simulations can guide material design and engineering, leading to the acceleration of new material discovery.

Antiferroelectric a kind of functional material that the antiparallel polarization gives rise to a double hysteresis loop. This unique behavior has potential applications in high-density energy storage devices. The properties of antiferroelectric materials is greatly influenced by the microdomain structures. Via the phase field simulation, the transformation behavior, mechanical property of microstructure, and defects induced nanopolar region can be theoretically understood.