Structural distortions imposed on cubic ferromagnets can induce significant perpendicular magnetic anisotropy (PMA) by reducing the crystalline symmetry, and hence enhance magnetic coercivity which is crucial for permanent magnets. It is a difficult task to maintain large enough homogeneous epitaxial strain in metallic bulk systems. In this work, by investigating the origin of PMA in Fe8Nx, we identify a novel route to engineer PMA by nitrogenation, which leads to distortions of both crystallographic and electronic structures.Read on

Magnetic refrigeration is an emergent technology that promises to be more energy efficient and eco-friendly than conventional cooling devices. At the basis of this technology is a thermodynamic cycle that exploits the magnetocaloric effect (MCE). In general, all magnetic materials experience an adiabatic temperate change upon removal of an applied magnetic field, this is the MCE. For real world devices however, an adequate material must meet several conditions, such as a strong MCE due to a magnetic transition near the room temperature, low hysteresis and absence of critical (rare-earths) or dangerous elements (arsenic). To date the search for search materials has mostly been an intensive experimental effort. An ongoing topic in our group has been to search for optimized or novel compounds that would serve as enablers of widespread magnetic refrigeration. We focus on two approaches: high-throughput search for new compounds and detailed calculations of phase transitions from first principles.

Read on

Analogous to perovskites, the antiperovskites are also one of the most commonly explored materials in recent years. Antiperovskites received huge attention due to their remarkable properties such as superconductivity, topological property, spin glass behavior, barocaloric effect, magnetoresistance, thermoelectric, magnetostriction, negative thermal expansion, and piezomagnetism. Our motivation in this study is to perform high throughput screening originated from the intriguing magnetic properties of antiperovskites. The main objective is to predict novel magnetic antiperovskites and validate the stability of existing antiperovskites. To our best knowledge this is the first high throughput screening of antiperovskites. In this work, we systematically carried out high throughput screening on 630 magnetic antiperovskites systems by using first-principles calculations to evaluate the stability.

Read on

High throughput design of 2D functional materials

The demand of minimization and feasibility of integration for future electronic devices makes two-dimensional (2D) materials remarkable in promising technological applications. Due to the breaking of translational symmetry, the 2D materials display more distinct properties than the corresponding bulk materials and thus are fundamentally interesting. For instance, the development of single atomic-layer graphene discovered in 2004 opens an avenue for exploring 2D materials, which provides multiple potential applications including electronics, spintronics, batteries and catalysts. 2D materials exhibit multiple electronic properties owing to different band gaps and electron behaviors. Moreover, from the chemical point of view, atoms in 2D materials are always exposed to the outside which leads to a high coefficient of atomic utilization. Therefore, chemical modification and charge transfer of 2D materials becomes much easier than that of bulk materials. Last but not least, the maturity of preparation methods (such as MBE and CVD growth) and development of analytic techniques provide a broad platform for synthesizing and modifying more 2D functional materials.

Read on