Giant room-temperature magnetodielectric coupling in spark plasma sintered brownmillerite ceramics

Journal Article · Mon Dec 01 00:00:00 EST 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4903479· OSTI ID:22402422

Wu, J. W.; Wang, J.; Liu, G.; Wu, Y. J.; Chen, X. M. ^[1]

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1. Laboratory of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

The dielectric, magnetic, and magnetodielectric properties of Ca{sub 2}FeAO{sub 5+δ} (A = Al, Ga) ceramics were investigated together with their crystal structures. Rietveld refinement of the X-ray diffraction data indicated that the space group of the Ca{sub 2}FeAlO{sub 5+δ} ceramic was Ibm2, whereas that of the Ca{sub 2}FeGaO{sub 5+δ} ceramic was Pcmn. Dielectric relaxation above room temperature, originating from the Maxwell–Wagner effect and polaronic hole hopping between Fe{sup 3+} and Fe{sup 4+} ions, was observed in both ceramics. Weak ferrimagnetic behavior was identified from the magnetic-field-dependent magnetization in these ceramics, which was attributed to the non-cancelled spins of the antiferromagnetic-ordered Fe{sup 3+} and Fe{sup 4+} ions. An intrinsic, giant, room-temperature magnetodielectric coefficient of up to −23.3% was achieved in the Ca{sub 2}FeAlO{sub 5+δ} ceramic at 50 MHz, which was attributed to the suppression of charge fluctuations of Fe{sup 3+} and Fe{sup 4+} ions in the magnetic field.

• OSTI ID: 22402422
• Journal Information: Applied Physics Letters, Vol. 105, Issue 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALUMINIUM OXIDES
ANTIFERROMAGNETISM
CALCIUM COMPOUNDS
CERAMICS
CRYSTAL STRUCTURE
GALLIUM OXIDES
HOLES
IRON COMPOUNDS
IRON IONS
MAGNETIC FIELDS
MAGNETIZATION
RELAXATION
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION