Silver niobate perovskites: structure, properties and multifunctional applications

Abstract

AgNbO3 exhibits “peculiar” anti-/ferroelectricity and narrow bandgap semi-conductivity that leads to active responses to different types of external stimuli, including electric fields, light and mechanical forces. Some of these unique...

Achieving Ultrahigh Energy Storage Density of La and Ta Codoped AgNbO3 Ceramics by Optimizing the Field-Induced Phase Transitions

“…The recent studies on AgNbO 3 consider the M 1 phase to be a ferroelectric phase. 22,34,38 Based on the previous XRD results, the room temperature phase M 1 of the AgNbO 3 ceramic conforms to the characteristics of the ferroelectric phase consisting of the polar ferroelectric phase and nonpolar The loss tangent of the ALNTx ceramics, unlike the undoped AgNbO 3 , does not change substantially with temperatures up to 250 °C. The improved stability of dielectric losses can be attributed to the more stable M 2b phase of the La 3+ and Ta 5+ codoped samples, when compared to the stability of the M 1 phase.…”

“…In consequence, the M 1 phase is stabilized at room temperature for AgNbO 3 , while the M 2b phase is stabilized at room temperature for ALNT0.01, ALNT0.02, and ALNT0.03. The recent studies on AgNbO 3 consider the M 1 phase to be a ferroelectric phase. ,, Based on the previous XRD results, the room temperature phase M 1 of the AgNbO 3 ceramic conforms to the characteristics of the ferroelectric phase consisting of the polar ferroelectric phase and nonpolar antiferroelectric phase. As for the ALNT x ceramics, the results of the previous structure refinements and TEM analyses indicate that the amount of local polar regions is reduced in the room temperature phase M 2b of the ALNT x ceramics, which contributes to the enhancement of antiferroelectricity.…”

“…The peculiarities of phase transitions of AgNbO 3 are still under debate. In particular, the properties of three orthorhombic phases (M 1 , M 2 and M 3 ) have not been fully understood. , It has been demonstrated that a proper chemical substitution of AgNbO 3 at A- and/or B-sites can induce a phase transition between the M 1 , M 2 , and M 3 phases, leading to the improved energy storage performance. ,, The temperature dependencies of the relative dielectric permittivity (ε r ) and loss tangent (tan δ) of the AgNbO 3 and ALNT x ceramics at four different frequencies, as collected on cooling from 450 °C down to room temperature, are shown in Figure . The ε r of the AgNbO 3 sample (Figure a) shows a sequence of dielectric anomalies around 50, 250, and 330 °C, which correspond to the known M 1 –M 2 , M 2 –M 3 , and M 3 –O phase transitions .…”

Antiferroelectrics and Magnetoresistance in La0.5Sr0.5Fe12O19 Multiferroic System

“…The traditional AFE materials, such as PbZrO 3 [ 18 ], AgNbO 3 [ 19 ], (Bi,Na)TiO 3 [ 20 ], (Pb,La)(Zr,Sn,Ti)O 3 [ 21 ], etc., are used to control and store electric energies and play a key role in mobile electronic devices, stationary power systems, hybrid electric vehicles [ 22 , 23 ]. These perovskites, however, can be charged electrically only.…”

Enhanced Energy Storage Properties in Lead-Free (Na0.5Bi0.5)0.7Sr0.3TiO3-Based Relaxor Ferroelectric Ceramics through a Cooperative Optimization Strategy

“…Ceramic dielectric capacitors with high power density, high voltage–resistance, and long life have become essential components in electronic systems. − However, the energy density of these capacitors is still insufficient to satisfy the requirements for integration and miniaturization of advanced electronic systems. , To store more energy, avoid energy loss, and adapt to high-temperature environments, it is necessary to produce ceramic capacitors with simultaneous excellent energy-storage density ( W rec ), energy-storage efficiency ( η ), and temperature stability . Generally, satisfactory W rec and η are theoretically dictated by the breakdown strength ( E b ) and difference (Δ P ) between the maximum polarization ( P m ) and remnant polarization ( P r ) according to the polarization versus electric field ( P – E ) hysteresis loops. , Thus, unlike linear dielectrics (LDs), ferroelectrics (FEs), and antiferroelectrics (AFEs), each of which has advantages and disadvantages, relaxor ferroelectrics (RFEs) have a large Δ P resulting from a large P m and a fast polarization response, and thus they exhibit potential energy-storage performance (ESP). − …”