Mechanism‐based tuning of room‐temperature ferromagnetism in Mn‐doped β‐Ga₂O₃ by annealing atmosphere

Abstract

Mn‐doped β‐Ga2O3 (GMO) films with room‐temperature ferromagnetism (RTFM) are synthesized by polymer‐assisted deposition, and the effects of annealing atmosphere (air or pure O2 gas) on their structures and physical properties are investigated. The characterizations show that the concentrations of vacancy defects and Mn dopants in various valence states and lattice constants of the samples are all modulated by the annealing atmosphere. Notably, the samples annealed in air (GMO–air) exhibit a saturation magnetization as strong as 170% times that of the samples annealed in pure O2 gas (GMO–O2), which can be quantitatively explained by oxygen vacancy (VO)‐controlled ferromagnetism due to bound magnetic polarons established between delocalized hydrogenic electrons of VOs and local magnetic moments of Mn2+, Mn3+, and Mn4+ ions in the samples. Our results provide insights into mechanism‐based tuning of RTFM in Ga2O3 and may be useful for design, fabrication, and application of related spintronic materials.

Structural and optical properties of Mg1−xMnxP2O6(x = 0–1.0) magnesium metaphosphate

“…This effect reduces the energy of the bandgap (E g ). Mn 2+ has a ground state configuration of 3d 5 . The electrons have a distribution of t 2g and e g orbitals in a moderate cubic crystal field.…”

“…Among the transition metal ions, Mn 2+ is one of the most exciting activators used in luminescence materials. Mn 2+ ion has an outer 3d 5 electron configuration, which shows the spin-forbidden 4 T 1 → 6 A 1 transitions in 3d shell. [1][2][3] When Mn 2+ is doped in an octahedral site, it can efficiently give red luminescence ( 4 T 1 → 6 A 1 ) under excitation of near ultraviolet or blue wavelength.…”

“…[1][2][3] When Mn 2+ is doped in an octahedral site, it can efficiently give red luminescence ( 4 T 1 → 6 A 1 ) under excitation of near ultraviolet or blue wavelength. Due to the typical d 5 electron configuration, the luminescence properties of Mn 2+ ions are closely related to the crystallographic environment. Therefore, the luminescence of Mn 2+ ions will be abundant with the change of the host materials.…”

“…The luminescence and application of Mn 2+ -activated luminescence material has been one of the research hot spots. [4][5][6] It has been found that phosphates possess rich structure types with high physical and chemical stabilities to ensure practical developments of Mn 2+ -activated phosphors in the fields of lighting and display. Among the kinds of phosphates, the polyphosphates containing the (P 4 O 12 ) 4− ring have been paid more attention in white light emitting diodes, plasma displays, optoelectronic devices, and biochemical probes, and so on.…”

“…Therefore, the luminescence of Mn 2+ ions will be abundant with the change of the host materials. The luminescence and application of Mn 2+ ‐activated luminescence material has been one of the research hot spots 4–6 …”