Anisotropic thermal expansion and electronic transitions in the Co3BO5 ludwigite
| Autor: | Natalia Kazak, Ana Arauzo, Juan Bartolomé, Maxim Molokeev, Vyacheslav Dudnikov, Leonid Solovyov, Andrew Borus, Sergei Ovchinnikov |
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| Přispěvatelé: | Russian Foundation for Basic Research, Agencia Estatal de Investigación (España), Ministerio de Economía, Industria y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Gobierno de Aragón |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| ISSN: | 0287-2021 |
| Popis: | The investigations of the crystal structure, magnetic and electronic properties of Co3BO5 at high temperatures were carried out using powder X-ray diffraction, magnetic susceptibility, electrical resistivity, and thermopower measurements. The orthorhombic symmetry (Sp.gr. Pbam) was observed at 300 K and no evidence of structural phase transitions was found up to 1000 K. The compound shows a strong anisotropy of the thermal expansion. A large negative thermal expansion along the a-axis is observed over a wide temperature range (T = 300–600 K) with αa = −35 M K−1 at T = 500 K with simultaneous expansion along the b- and c-axes with αb = 70 M K−1 and αc = 110 M K−1, respectively. The mechanisms of thermal expansion are explored by structural analysis. The activation energy of the conductivity decreases significantly above 700 K. Electronic transport was found to be a dominant conduction mechanism in the entire temperature range. The correlations between the thermal expansion, electrical resistivity, and effective magnetic moment were revealed and attributed to the evolution of the spin state of Co3+ ions towards the spin crossover and gradual charge-ordering transition. We are grateful to the Russian Foundation for Basic Research (project no. 20-02-00559 and 21-52-12033) for supporting this paper. This work was performed within the framework of the budget project no. 0287-2021-0013 for the Institute of Chemistry and Chemical Technology SB RAS. We acknowledge the financial support from the Spanish Ministry of Economy, Industry and Competitiviness (MINECO), (Grant No. MAT2017-83468-R) and from the regional Government of Aragón (E12-20R RASMIA project). |
| Databáze: | OpenAIRE |
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