Multiferroic and magneto-dielectric properties in Fe doped BaTiO3

Abstract

Polycrystalline barium titanate (BTO) samples doped with infinitesimal quantity of iron separately and simultaneously in both A and B sites are prepared using solid state reaction method with an emphasis on its site preference. Structural studies establish the transformation from tetragonal to pseudo-cubic phase upon changing the dopant site. An appreciable compressive lattice strain is induced when Fe is doped in the A-site while it becomes tensile and negligibly small when Fe occupies B-site. Further, the suppression of 308 cm−1 band in the Raman spectra highlights the coexisting cubic and tetragonal phases in A-site doped BTO. Ferroelectric ordering is validated using P–E loop and PUND (positive up and negative down) measurements. Dielectric constant undergoes a transition from ferroelectric to paraelectric state at 388 K for BTO and it varies with occupation site of Fe. Low temperature magnetic measurements reveal the strong antiferromagnetic coupling in A-site doped BTO sample. Magneto-dielectric measurements portray the proper choice of doping site in BaTiO3 so as to introduce multiple magnetic and electric states in it.