Magnetite (Fe3O4): a new variant of relaxor multiferroic?

• Published in: Journal of physics. Condensed matter Vol. 24; no. 8; pp. 86007 - 10
• Main Authors: Ziese, M, Esquinazi, P D, Pantel, D, Alexe, M, Nemes, N M, Garcia-Hernández, M
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 29.02.2012; Institute of Physics
• Subjects: Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electric polarization; Exact sciences and technology; Ferroelectricity and antiferroelectricity; Heat capacity; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Magnetite; Magnetization; Magnetomechanical and magnetoelectric effects, magnetostriction; Permittivity (dielectric function); Phase transitions and curie point; Physics; Polycrystals; Relaxors; Specific heat; Frequency dependence; Iron oxide; Magnetization; Polycrystals; Verwey transition; Relaxor; Magnetic susceptibility; Thin films; Specific heat; Ferroic material; Ferroelectric transitions; Dielectric polarization; Magnetite; Magnetoelectric effects; Permittivity
• ISSN: 0953-8984; 1361-648X; 1361-648X
• DOI: 10.1088/0953-8984/24/8/086007

The electric polarization, dielectric permittivity, magnetoelectric effect, heat capacity, magnetization and ac susceptibility of magnetite films and polycrystals were investigated. The electric polarization of magnetite films with saturation values between 4 and 8 µC cm−2 was found to vanish between 32 and 38 K, but in polycrystals no phase transition was detected in this range by heat capacity. Both types of samples showed magnetoelectric effects at low temperatures below a frequency-dependent crossover. This is interpreted as arising from multiferroic relaxor behavior.