Room temperature ferromagnetism driven by Ca-doped BiFeO3 multiferroic functional material

Herein through the study of structural, electrical, and magnetic properties of Ca-doped bismuth ferrite Bi1−xCaxFeO3-(x/2)+δ, Rietveld analysis of the X-ray diffraction patterns shows a tendency of structural phase transition from hexagonal into tetragonal structure by Ca-doping ratio of x = 0–0.3. The transport measurement also shows the phase transitions from metallic (paramagnetic) into insulator (anti-ferromagnetic) ordered with Néel temperature from 600 to 700 K. The magnetic moment versus magnetic field measurement confirms the structural phase transitions by switching the coercivity from hard to soft ferromagnetic state at room temperature. It was concluded that insertion of Ca+2 dopants substituting Bi+3 facilitates enhancement of the charge ordering and through which the ease to switch between double exchange into direct exchange mechanism.