Unit cell volume reduction of Gd5(Si,Ge)4 nanoparticles controlled by bulk compressibility

Autor: Andrade, Vivian Maria Campos Soares de
Přispěvatelé: UNIVERSIDADE ESTADUAL DE CAMPINAS
Rok vydání: 2020
Předmět:
Zdroj: Repositório Institucional da Unicamp
Universidade Estadual de Campinas (UNICAMP)
instacron:UNICAMP
Repositório da Produção Científica e Intelectual da Unicamp
Popis: Agradecimentos: This work is funded by FEDER funds through the COMPETE 2020 Programme and National Funds throught FCT - Portuguese Foundation for Science and Technology under the project UID/NAN/50024/2013 and by NECL with the project NORTE-01-0145-FEDER-022096. This work was also supported by the European Union’s Horizon -2020 research, innovation program under the Marie Sklodowska-Curie Grant Agreement No. 734801 and by the Fundação de Amparo a Pesquisa do Estado de São Paulo, Brasil (FAPESP) - Project No. 2017/10581-1. The authors would like to thank LABNANO/CBPF for the grants and technical support. We would also like to thank Prof. Kleber R. Pirota for reading the manuscript and contribute with suggestions that were important for the work evaluation. VMA thanks the CNPq for the Grant No. 203180/2014-3. J.H. Belo thanks FCT for the Grant SFRH/BD/88440/2012, the project PTDC/FIS-MAC/31302/2017 and his contract DL57/2016 reference SFRH-BPD-87430/2012. MSR thanks CNPq and FAPERJ for financial support. He belongs to the INCT of Refrigeração e Termofísica, funding by CNPq by Grant No. 404023/2019-3 Abstract: The production of Gd-5(Si,Ge)(4) compounds in reduced dimensionality, through pulsed laser deposition (PLD), have shown their potential for practical applications. Here, we present nanoparticles ranging from 10 to 27 nm of average particle size of Gd-5(SixGe1-x)(4), with x = 0, 0.45 and 0.60, obtained using an Nd:Yag (1064 nm) and an Excimer KrF laser (248 nm). Synchrotron X-ray Diffraction measurements revealed a reduced unit cell volume in comparison to their bulk counterpart. The x = 0 sample presented a similar to 1.99% reduction while x = 0.45 composition, a shrinkage of similar to 1.81% on the unit cell volume that are a result of a structural change to a Gd5Si4-type structure [O(I)]. In contrast, x = 0.60 nanoparticles conserve the bulk crystal structure with similar to 0.95% of volume shrinkage. As a consequence, there is a change on the magnetic transition order from a first to a second one for all nanostructures followed by a magnetocaloric response reduction. These observations unveil a direct correlation between the bulk compressibility values and the unit cell shrinkage, suggesting that the rise of a surface stress plays a major role on the particle and unit cell dimensions FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJ Fechado
Databáze: OpenAIRE
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