resumo
Research on topological defects in hexagonal manganites exposed uncovered properties of topologically protected domains and domain walls. Topological defects of h-REMnO3 oxides (RE = Lu-Dy and Sc, In) modify essential multiferroic properties. Despite wide research with single crystals of stoichiometric composition, for the case of polycrystalline ceramics rare studies explored the effects of adjustment in chemical composition on phase transition temperatures, antiferromagnetic ordering, topological domain sizes, and potential modifications of the vortex density predicted by the Kibble-Zurek mechanism (KZM). The effect of cation vacancy doping of either Mn, or Lu sublattices of h-LuMnxO3, on appearance of ferroelectric vortices at the Curie point of apolar-to-polar ferroelectric ordering, T-C, in bulk ceramics is investigated here. For cooling rates up to 40 K min(-1) the Kibble-Zurek mechanism sets the density of FE vortices in ceramics of the LuMnxO3 system. Magnetic hysteresis loops taken from the representative samples show sensitivity of remnant and magnetic coercivity field to FE vortex density. Magnetization measured from magnetic hysteresis loops supports theoretical predictions on induced net magnetization of the AFM walls and gives further evidence on the essential role of FE domain walls on multiferroic properties of h-REMnO3.
palavras-chave
MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURE; DEFECTS; PHASE; FERROELECTRICITY; CONDUCTIVITY; OXYGEN
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Baghizadeh, A; Vaghefi, PM; Alikin, DO; Amaral, JS; Amaral, VS; Vieira, JM
nossos autores
Ali Baghi Zadeh
Bolseiro de pós-Doutoramento
Denis Alikin
Investigador Auxiliar
João Cunha de Sequeira Amaral
Investigador Auxiliar
Joaquim Manuel Vieira
Professor(a) Jubilado(a)
Pegah Mirzadeh Vaghefi
Bolseiro de pós-Doutoramento
Vitor Brás Sequeira Amaral
Professor Catedráticoagradecimentos
A.B. acknowledges the FCT fellowship SFRH/BDP/115625/2016. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement.