engleski

Magnetic behaviour of Ag doped BiFeO3

Bismuth ferrite (BFO) is one of the few room temperature magneto-electric multiferroics. High ferroelectric and magnetic transition temperatures (1100 K and 630 K respectively) makes it interesting for possible technological application. The problem with bulk ceramic form of BFO is low net magnetic moment of its ordered antiferomagnetic phase. To disturb the antiferromagnetic order and induce bigger magnetic moment, BFO is often doped with different elements, usually heavy rare earth elements or transition metal ions. In this study we have investigated magnetic behaviour of Ag doped BFO. Compounds of BiFeO3, in which metal ions are substituted with different percentage of silver, were synthesized using hydrothermal method. Structural characterization of obtained samples was performed by X-ray diffraction. Magnetization of polycrystalline samples measured on a wide temperature range, from 2 K to 720 K, showed that the transition temperature for all the samples is nearly the same, TN = 630 K. The development of weak ferromagnetism with doping was observed as enhanced splitting between zero field cooled (ZFC) and field cooled (FC) curves, together with increased magnetization seen also in M(H) curves. The peculiar behaviour of ZFC and FC curves where, at lower temperatures, the FC curve crossed the ZFC curve attaining lower values of magnetization then the ZFC curve, could be attributed to the competition of exchange interactions within and between the sublattices. Acknowledgment: The authors acknowledge the financial support of the Croatian Science Foundation under the project UIP-2014-09-8276.

Bismuth ferrite ; Multiferoics ; Magnetoelectric effect

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