Insulator-Metal Transition in the Nd2CoFeO6 Disordered Double Perovskite

Autor(es)

de Oliveira, Leonardo S. ^[1] ; Sabino, Fernando P. ^[1] ; de Florio, Daniel Z. ^[1] ; Janotti, Anderson ^[2] ; Dalpian, Gustavo M. ^[1] ; Souza, Jose A. ^[1]

Afiliação do(s) autor(es)

^[1] Fed Univ ABC, BR-09210580 Santo Andre, SP - Brazil

^[2] Univ Delaware, Dept Mat Sci & Engn, Newark, DE 19716 - USA

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 124, n. 41, p. 22733-22742, OCT 15 2020.
• Citações Web of Science: 0

Resumo

A comprehensive study on the correlations of structural, magnetic, and electronic properties of a new disordered Nd2CoFeO6 double perovskite has been conducted. The lack of A strong divergence of the magnetic susceptibility suggests competition between magnetic interactions at the magnetic phase transition T-N = 246 K, which is confirmed by the absence of a heat capacity peak. The magnetic susceptibility results indicate that the Fe/Co spins form a classical noninteracting paramagnetic state above T approximate to 2.2T(N), while deviations are found at intermediate temperatures indicating the presence of strong short-range magnetic interactions. AC and DC electrical resistivity results reveal a melting of insulating polaronic behavior to a metallic-like conductivity, establishing an electronic crossover closely related to both local magnetic moment and lattice-parameter evolution. We show from density functional calculations that the magnetic configurations have a strict relation to this crossover, being associated to a transition from low to high spin states of Co3+ ions. This insulator-metal transition has its origin driven by a local increase in the magnetic moment of Co3+ ions. Our results point to a scenario in which a continuous spin-state transition triggers a crossover between distinct electronic states from the insulating polaronic behavior to permanent metallic states. (AU)

• Processo FAPESP: 15/24999-2 - Novos compostos cerâmicos para células a combustível de óxidos sólidos protônicas
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