Magnetoelectric and magnetodielectric coupling and microwave resonator characteristics of Ba_0.5Sr_0.5Nb₂O₆/CoCr_0.4Fe_1.6O₄ multiferroic composite.

ABSTRACT: A multiferroic composite consisting of single phases of 30 vol.% magnetostrictive ferrite and 70 vol.% relaxor ferroelectric has been synthesized. The ferrite exhibits a diffuse dielectric phase transition (DPT)with the transition temperature varying from 450?K to 600?K and an activation energy of 0.29?eV. Magnetically, it has a soft behavior with 70 emug^-1 saturation magnetization and a Curie transition at ~620?K. The relaxor ferroelectric phase on the other hand exhibits two clear DPTs at 390?K-400?K and 150?K-300?K. The composite of these two shows a soft ferromagnetic behavior reminiscent of the ferrite along with 3 DPTs. There is strong coupling between the two orders - magnetostrictive and piezoelectric in the composite. The capacitance decreases by 45% in the presence of magnetic field corresponding to a sensitivity of 0.9% kOe^-1, an extremely large value. The magnetoelectric coupling constant is found to be 20.6 mVcm^-1Oe^-1, a large value for a bulk composite. Microwave band stop filters of different thicknesses made from the composite have resonant frequencies which upshift in the presence of magnetic field indicating a multiferroic behavior with possibility for electric field tuning of resonant frequency.

SUBMITTER: Tiwari S 

PROVIDER: S-EPMC6072765 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature