Magnetoelectric coupling-induced anisotropy in multiferroic nanocomposite (1 − x)BiFeO3–xBaTiO3

Abstract

Nanocomposite (1 − x)BiFeO3–xBaTiO3 for x = 0.1, 0.2 and 0.3 compositions were prepared by sol–gel technique. X-ray diffractograms confirmed the formation of desired crystallographic phase of the composite. The average particle size was determined 75, 128 and 150 nm for x = 0.1, 0.2 and 0.3 samples by HRTEM measurement. Magnetic, dielectric and magnetoelectric response has been investigated to find out the magnetoelectric (ME) coupling at atomic scale mixing of the two phases. For effective ME coupling nanoscale synthesis provided large surface area and subsequently induced magnetic anisotropy in the sample. The computed value of magnetic anisotropy constant 4.8 × 103 erg/cm3 was found to be maximum for x = 0.1 composition. It is believed that the anisotropy is being induced by ME coupling which changes with the composition. Correlated magnetic and dielectric transition temperatures were determined as an evidence of ME coupling in the material. To confirm the ME coupling room-temperature ME coupling coefficient (α) was calculated using dynamic method which was observed to have a maximum value of 2.74 mV/cmOe for x = 0.1 confirming the presence of room-temperature ME coupling in the nanocomposite. Spin flipping behaviour has been confirmed by ZFC–FC measurements at low temperature while the coercivity was found to be almost constant. Significantly, controlled coercivity behaviour has been correlated to the presence of ME coupling in the composite material, which can be very useful in memory device and spintronic application.