Ferroelectricity of Dion-Jacobson layered perovskites CsNdNb${}_2$O${}_7$ and RbNdNb${}_2$O${}_7$

Abstract

Crystallography and dielectric properties in Dion-Jacobson layered perovskites, CsNdNb${}_2$O${}_7$ and RbNdNb${}_2$O${}_7$, have been examined in dense polycrystalline samples, and polarization hysteresis loops that substantiate ferroelectricity have been observed at room temperature. The theoretical mechanism for the spontaneous polarization, "hybrid improper ferroelectric mechanism,'' induced by a combination of two types of non-polar octahedral rotations, is confirmed in these two phases. Our samples show remanent polarizations of 2-3 $\mu$C/cm${}^2$, which are much larger than those obtained in polycrystalline samples with the hybrid improper ferroelectricity reported so far. A dielectric constant in CsNdNb${}_2$O${}_7$ exhibits an anomaly at 625 K, corresponding to the ferroelectric transition, as previously revealed by x-ray and neutron diffractometry. No dielectric anomaly is observed for RbNdNb${}_2$O${}_7$ throughout the temperature range studied here ($\le$ 773 K), which is consistent with the previous diffractometry showing the persistence of polar $I2cm$ symmetry up to 790 K.

arXiv comment7 pages, 3 figures, accepted for publication by JJAP

References in corpus (8)

• Experimental demonstration of hybrid improper ferroelectricity and presence of abundant charged walls in (Ca,Sr)${}_3$Ti${}_2$O${}_7$ crystals
• Octahedral rotation-induced ferroelectricity in cation ordered perovskites
• Turning ABO${}_3$ antiferroelectrics into ferroelectrics: Design rules for practical rotation-driven ferroelectricity in double perovskites and A${}_3$B${}_2$O${}_7$ Ruddlesden-Popper compounds
• Polar octahedral rotations: a path to new multifunctional materials
• Direct observation of ferroelectricity in Ca${}_3$Mn${}_2$O${}_7$ and its prominent light absorption
• Domains and ferroelectric switching pathways in Ca${}_3$Ti${}_2$O${}_7$ from first principles
• Ferroelectricity in the Dion-Jacobson CsBiNb${}_2$O${}_7$ from first principles
• Octahedral tilting and ferroelectricity in RbANb2O7 (A = Bi, Nd) from first principles

Cited by in corpus (1)

• Revival of Layered Ferroelectrics in Thin Films