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POSTER CONTRIBUTIONS
Hematite sub-micron hollow spheres: Thermal formation and
magnetic properties
Luis De Los Santos Valladares 1,2 , L. León-Félix. 3,4 , A. Bustamante 3 , M. Espinoza Suárez 3 , J.
Albino Aguiar 2
1
Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson
Avenue, Cambridge CB3 0HE, United Kingdom.
2
Laboratório de Supercondutividade e Materiais Avançados, Departamento de Física,
Universidade Federal de Pernambuco 50760-901, Recife, Brazil.
3
Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad
Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima, Perú.
4 Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, DF 70910-
900, Brazil.
In this work, we report the thermal formation and magnetic properties of α-Fe 2 O 3 submicron
hollow spheres. X-ray diffraction analysis confirms the formation of the α-Fe 2 O 3
phase after sintering at 773, 823 and 823 K. Scanning electron microscopy images
reveal the formation of hollow spheres after the sintering at 823 K. The evolution of the
Morin transition is studied by magnetic measurements. Mössbauer spectroscopy
measurements at room temperature and 77 K show that the hyperfine parameters depend
on the temperature of annealing and indicate the occurrence of the Morin transition in
the hollow spheres.
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