Tourmalines pyroelectric effect depending on the chemical composition and cation oxidation state

• Published in: Journal of solid state chemistry 2021-11, Vol.303, p.122512, Article 122512
• Main Authors: Chernyshova, Irina A., Vereshchagin, Oleg S., Malyshkina, Olga V., Goncharov, Aleksey G., Kasatkin, Igor A., Murashko, Mikhail N., Zolotarev, Anatoly A., Frank-Kamenetskaya, Olga V.
• Format: Article
• Language: English
• Subjects: "Composition - structure - properties" correlations; Crystal chemistry; Dynamic pyroelectric measurement method; Ion oxidation state; Pyroelectric effect; Tourmaline
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2021.122512

Tourmaline (the first natural pyroelectric material discovered) is the most common borosilicate on Earth characterized by a great variety of ionic substitutions at all structural sites. In this work the mosaicity and chemical inhomogeneity of single crystal samples of natural Fe-Mg and synthetic Ni- and Cu-rich tourmalines were characterized by X-ray diffraction (rocking curves, ω – 2θ scanning) and energy-dispersive X-ray spectroscopy. The iron oxidation state (Fe3+/ΣFe) in natural tourmalines was determined by Mӧssbauer spectroscopy. The pyroelectric properties of tourmalines were examined at room temperature by the dynamic pyroelectric measurement method. This approach allowed estimating the primary pyroelectric coefficient with the error smaller than ±0.15 μCm-2K-1. Based on the original and published data, it was shown that one of the main factors determining the pyroelectric properties of tourmaline is the ion oxidation state. It was found that the values of the Na-tourmaline pyroelectric coefficient were inversely proportional to the amount of divalent cations (Mg, Fe) and/or directly proportional to the amount of Al3+. This can be used for the directed synthesis of tourmalines with the required pyroelectric properties. [Display omitted] •Octahedral cations oxidation state influences on tourmalines pyroelectric properties.•Decreasing of divalent cations leads to increasing of tourmaline γ.•Pyroelectric coefficient of tourmaline increases with monovalent cations increasing.•Pyroelectric coefficient of tourmaline increases with trivalent cations increasing.•Based on the original data, synthesis of tourmalines with enhanced γ can be improved.