Nanocrystalline CoFe2O4 and Co0.5M0.5Fe2O4 (M = Mn, Ni, and Zn) ferrites were prepared by solution combustion method using oxalyl dihydrazide as a fuel. These materials were characterized by several physicochemical...

In this study, we determined the different physical characteristics of nanoscale layered mixed Fe-Co layers of orthoferrite SmFe 0.5 Co 0.5 O 3 based on magnetic and dielectric measurements.Magnetization analyzes showed that the system was antiferromagnetic with a magnetic transition around 310 K and two spin-reorientation transitions at around 192 K and 22 K. In this phase, the antisymmetric exchange interaction induced weak ferromagnetism due to canting of the magnetic spins in a similar manner to the Ln-Fe-Co system. Importantly, this nanoscale layered perovskite also exhibited a positive magneto-dielectric effect of around 2.5% (100 K) and the value decreased on both sides of this temperature. We analyzed the conditions related to the existence of magnetic and dielectric coupling in terms of the magnetic interactions between the cations as well as the spin-lattice interactions in the low temperature range.

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The mixed ferrite-cobaltites LnFe 0.5 Co 0.5 O 3 , with Ln = Eu & Dy have been prepared by a sol-gel method and the samples have been characterized using X-ray diffraction and electron microscopy. The magnetic investigations reveal that both samples ordered in canted antiferromagnetic structures near room temperature. The Dzyaloshinskii-Moriya or antisymmetric exchange interaction induces weak ferromagnetism due to canting of the antiferromagnetically ordered spins. In the case of Ln-Fe-Co orthoferrites, two magnetic sublattices (Ln 3+ -4f and Fe 3+ /Co 3+ -3d) generally align in opposite directions and interesting temperature dependent phenomena: e.g. uncompensated antiferromagnetic sublattices and spin-reorientations, are observed in the system. The existence of hysteresis at low temperature region has been explained in terms of the strength of magnetic interactions between Fe 3+ and Co 3+ ions with different A-site rare earth cations.

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