Phase diagrams and ferroelectric properties of a nanoparticle with antiferroelectric core/ ferroelectric shell morphology

In this work, we provide an exhaustive analysis of the ferroelectric and thermal properties, as well as the phase diagrams of a nanoparticle with antiferroelectric core/ferroelectric shell described by the effective field theory. Our strategy relies on the use of the suitability core-shell structure, which allows tuning of interface at various scales. For this purpose, several physical quantities were systematically investigated including the longitudinal polarization, pyroelectric coefficient, internal energy, specific heat, and entropy. The influences of the core exchange interaction J(c)/J(s) and transverse field Omega/J(s) on the aforementioned properties and phase diagrams are discussed in detail, which both have a considerable implications regarding the critical temperature (T-c), and could represent an important step towards better understanding of this aspect. Through a detailed analysis, the results indicate that J(c)/J(s) affects substantially the physical quantities, however, the internal energy exhibits an inflection point in the vicinity of T-c. Interestingly, our results showed that a variation of J(c)/J(s) and Omega/J(s) could lead to diverse results pertained to the critical behavior. The phase diagrams in the (T-c/J(s), J(1)/J(s)), (T-c/J(s), Omega/J(s)), and (T-c/J(s), Omega(c)/J(s)) coordinates are constructed. Consequently, the increase of vertical bar J(c)/J(s)vertical bar enlarges noticeably the magnitude of the ordered state. Besides, the increase of Omega/J(s) shrinks the ordered state and thus T-c. Our study implies the important role played by J(c)/J(s) to appropriately controlling the transition temperature, which may provide a further insight into the effect ofJ(c)/J(s) on the critical properties. Typical ferroelectric hysteresis behaviors were probed detailedly to confirm the order-disorder character. Our approach could provide a guidance to design ferroelectric nanomaterials while controlling the exchange couplings.

Automated summary

This study provides an exhaustive analysis of the ferroelectric and thermal properties, as well as phase diagrams, of a nanoparticle with antiferroelectric core/ferroelectric shell. The results indicate that the core exchange interaction and transverse field have considerable implications on critical temperature and properties. The study suggests the important role played by the core exchange interaction in controlling the transition temperature and provides insights into its effect on critical properties.