Tuning Magnetic Properties of BiFeO₃ Thin Films by Controlling Rare-Earth Doping: Experimental and First-Principles Studies

Abstract

Rare Earth (RE) -doped BiFeO 3 (BFO) thin films were grown on LaAlO 3 (LAO) substrates by using pulsed laser deposition technique. All of BFO films doped with 10% of RE exhibit a rhombohedral single phase. As for the Pr and Nd doping cases, the ferromagnetic phase is less favored because Fe 2+ amount is not dominant. When dopant concentration was increased up to 20%, the RE-doped BFO films have gone through a structural transition from rhombohedral to either pure orthorhombic phase (for Ho, Sm), or a mixed phase of orthorhombic and tetragonal (for Pr, Nd), or pure tetragonal (for Eu). As an important consequence, magnetic properties of RE-doped BFO films have drastically changed. Our results give a guide for how to tailor the ferromagnetism of BFO films by appropriate controlling the type of RE dopant as well as dopant concentration. The experimental findings are completed by performing density functional theory calculations to explore the effect of RE doping in BFO for the considered three phases.

Structural and Magnetic Properties of Mn Doped BiFeO3 Nanomaterials

“…The enhanced magnetization was observed in BFO due to the divalent, trivalent, and rare earth ions on Fe site [7,8]. Literature suggests that the superexchange interaction within Fe 3+ -O-Fe 2+ gives rise to a finite value of magnetization in BFO [9]. The enhanced magnetization in Mn and Ho doped BFO thin films prepared by chemical solution deposition was due to the collapse of space modulated spin structure by the structural transition [10].…”

Low Dielectric Loss and Multiferroic Properties in Ferroelectric/Mutiferroic/Ferroelectric Sandwich Structured Thin Films

“…However, BFO has remained unsuitable, due to its high leakage current and large dielectric loss [4][5][6]. Magnetic properties can be adjusted by using Nd 3+ ions instead of larger Bi 3+ ions in the BFO composition [7], and in order to improve leakage current, Ni, Ti, Sm, Mn, Zn, and Ho doped in BFO thin films [8][9][10][11][12][13][14], to improve ferroelectric properties and ferroelectric properties, but there was limited action in reducing leakage current. Due to its nonlinear dielectric properties, (Ba,Sr)TiO 3 has been widely used in electronic devices [15][16][17]; however, there is low remnant polarization and coercive electric field in the (Ba,Sr)TiO 3 thin film.…”

Tuning Ferroelectric, Dielectric, and Magnetic Properties of BiFeO3 Ceramics by Ca and Pb Co‐Doping

“…For the bulk BFO, the symmetry favors the canted antiferromagnetic coupling, resulting in a non‐zero magnetization . However, a spiral spin structure with period of ≈62 nm arising from the canted spin cancels out any net magnetization . Moreover, the large leakage current at room temperature (RT) is a major obstacle for its practical application.…”