Fabrication and Magnetic Properties of Multiferroic BiFeO3 Nanotube Arrays

Abstract Multiferroic BiFeO3 nanotube arrays have been successfully prepared by means of a sol–gel method utilizing porous anodic alumina templates. The magnetic field and temperature dependencies of magnetizations demonstrate the superparamagnetism behavior with the most sound evidence, which can be attributed to the uncompensated surface spins induced by the size effect.