Prominent electrochromism through vacancy-order melting in a complex oxide

Abstract

Electrochromes are materials that have the ability to reversibly change from one colour state to another with the application of an electric field. Electrochromic colouration efficiency is typically large in organic materials that are not very stable chemically. Here we show that inorganic Bi 0.9 Ca 0.1 Feo 3 − 0.05 thin films exhibit a prominent electrochromic effect arising from an intrinsic mechanism due to the melting of oxygen-vacancy ordering and the associated redistribution of carriers. We use a combination of optical characterization techniques in conjunction with high-resolution transmission electron microscopy and first-principles theory. The absorption change and colouration efficiency at the band edge (blue-cyan region) are 4.8×10 6 m − 1 and 190 cm 2 C − 1 , respectively, which are the highest reported values for inorganic electrochromes, even exceeding values of some organic materials.

Mn substitution-induced revival of the ferroelectric antiferromagnetic phase in Bi1−x Ca x FeO3−x/2 multiferroics

“…Reversible modulation of electric conduction and a prominent electrochromic effect arising in Ca-doped BiFeO 3 as a consequence of the field-induced spatial movement of naturally produced oxygen vacancies (which act as donor impurities to compensate Ca acceptors and maintain a highly stable Fe 3? valence state) make this material very promising for future technological applications [21][22][23]. The general conception that would predict properties of BiFeO 3 under the chemical pressure is not yet designed, so a searching for the conditions favoring coexistence of the spontaneous magnetization and polarization in a single phase still remains one of the most challenging tasks of the modern multiferroic research.…”

Strain-induced magnetic phase transition inSrCoO3−δthin films

“…The broad range of transition metal oxide functionalities, including superconductivity, magnetism, and ferroelectricity, can be tuned by the careful choice of parameters such as strain, oxygen content, or applied electric and magnetic fields [1][2][3][4][5][6][7][8][9] . This tunability makes transition metal oxide materials ideal candidates for use in developing novel information and energy technologies 10,11 .…”

Oxygen‐vacancy‐controlled magnetic properties with magnetic pole inversion in BiFeO3‐based multiferroics

“…Due to its high ferroelectric Curie temperature (1103 K) and antiferromagnetic Néel temperature (643 K), BFO is one of the most promising single‐phase multiferroics and has attracted a lot of attention . Notably, the intrinsic defects of oxygen vacancies in BFO can significantly impact its properties, such as changing the fatigue behavior, remnant polarization and thermal conductivity, increasing the leakage current, and inducing dielectric relaxation and magnetodielectric, weak ferromagnetism, and electrochromism . However, the correlation between oxygen vacancies and magnetism is still poorly understood, especially, the effects of oxygen vacancies on magnetic pole inversion have not been studied.…”

“…[4][5][6][7] Notably, the intrinsic defects of oxygen vacancies in BFO can significantly impact its properties, 8 such as changing the fatigue behavior, remnant polarization 9,10 and thermal conductivity, 11 increasing the leakage current, 12,13 and inducing dielectric relaxation and magnetodielectric, 14 weak ferromagnetism, 15,16 and electrochromism. 17 However, the correlation between oxygen vacancies and magnetism is still poorly understood, especially, the effects of oxygen vacancies on magnetic pole inversion have not been studied. One challenge is to control the concentration of oxygen vacancies while maintaining phase purity.…”