Enhanced Multiferroic Properties of YFeO3 by Doping with Bi3+

Abstract

Tthe present work studied the cationic substitution of Y3+ by Bi3+ on the crystal structure of orthorhombic YFeO3 and its effect over magnetic, dielectric and electric properties of multiferroic yttrium orthoferrite. Stoichiometric mixtures of Y2O3, Fe2O3 and Bi2O3 were mixed and milled for 5 h using a ball to powder weight ratio of 10:1 by high-energy ball milling. The obtained powders were pressed at 1500 MPa and sintered at 700 °C for 2 h. The test samples were characterized at room temperature by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and impedance spectroscopy (IS). The X-ray diffraction patterns disclosed a maximum solubility of 30 % mol. of Bi3+ into the orthorhombic YFeO3. For higher concentrations, a transformation from orthorhombic to garnet structure was produced, obtaining partially Y3Fe5O12 phase. The substitution of Bi3+ in Y3+ sites promoted a distortion into the orthorhombic structure and modified Fe-O-Fe angles and octahedral tilt. In addition, it promoted a ferromagnetic (FM) order, which was attributed to both the crystal distortion and Dzyaloshinskii-Moriya interaction. For doped samples, an increase in real permittivity values was observed, and reduced with the increase of frequency. This in good agreement with the Maxwell-Wagner effect.

Structural, ferroelectric, and optical properties of Bi3+ doped YFeO3: A first‐principles study

“…Therefore, the ground‐states of YFO and YFO‐Bi are AFM. This result coincides with the experimental works reported in references 4,10. Here, we have only considered the AFM‐G configuration (see Figure 1).…”

“…The 25% Bi doping of YFO is within the studied range of impurification keeping the orthorhombic structure with space group D2h‐Pnma . [ 10,12 ] There is an increase in the lattice parameters in the YFO‐Bi structure with respect to that of the YFO, a = 5.756 Å, b = 7.824 Å and c = 5.433 Å, attributed to the ionic radius of Bi (1.03 Å) being larger than that of Y (0.90 Å). [ 20 ] To determine the ground‐state magnetic order, we compared the total energies of ferromagnetic (FM) and G‐type (AFM‐G) antiferromagnetic ordering for both YFO and YFO‐Bi.…”

“…[ 5 ] Many works are focused on the effects of the magnetic properties of YFeO 3 upon doping of the A (Y 3+ ) or B (Fe 3+ ) sites with different ions (Ca, Gd, Er, Mn, Ti, Bi). [ 2,6–10 ] However, there are hardly any reports on their ferroelectric properties. From a theoretical point of view, Zhang et al [ 11 ] studied the effect of Y (6.25%) substitution on the structural and electronic properties of BiFeO 3 using density functional theory calculations.…”

Estudio de las propiedades dieléctricas de Ba1-xCaxTiO3 obtenido por molienda mecánica de alta energía

“…Los mayores valores de permitividad a bajas frecuencias pueden ser atribuidos a la polarización espacial de las cargas debido a límites de grano, defectos y vacancias como lo predice el efecto Maxwell-Wagner. A frecuencias más altas, los dipolos responsables de la polarización no pueden seguir las oscilaciones del campo eléctrico aplicado, por lo cual los valores de permitividad relativa disminuyen [15]. De manera general se observa un incremento en los valores de ε r para las muestras que contienen Ca 2+ , encontrando los mayores valores para la muestra con x=0.05.…”

Modificación de las propiedades multiferroicas de BiFeO3 dopada con Y3+

“…El incremento en la conductividad generalmente es asociado a un incremento en los portadores de carga producidos por la presencia o incremento de vacancias de oxígeno en el material. Las vacancias de oxigeno se pueden generar de varias maneras, siendo comúnmente asociadas al tratamiento térmico de los materiales y distorsión en la estructura [17]. De igual manera la presencia de fases secundarias propiciada por la volatilización del Bi 3+ durante el tratamiento térmico.…”