Related Experiment Video
Updated: Jun 8, 2025
Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
p-Orbital Ferromagnetism Arising from Unconventional O- Ionic State in a New Semiconductor Sr2AlO4 with
Xu-Guang Zheng1,2, Chao-Nan Xu1, Tomoki Uchiyama1
1Department of Materials Science and Engineering, Faculty of Engineering, Tohoku University, Sendai, 980-8579, Japan.
Abstract:
Oxygen in solids usually exists in an O2- ionic state. As a result, it loses its magnetic nature of a single atom, wherein two unpaired electrons exist in its outer 2p orbitals. Here, it is shown that an unconventional stable ionic state of O- is realized in a new semiconductor material Sr2AlO4, leading to an intrinsic p-orbital ferromagnetism stable until ≈900 K. Experimental and theoretical investigations have clarified that one-fourth of the oxygen atoms in Sr2AlO4 are insufficiently bonded in the crystal structure, resulting in a unique O--state and p-orbital ferromagnetism. To date, the O- state is reported to exist only in non-equilibrium conditions, and p-orbital magnetism is only suggested in impurity bands with small ferromagnetic moments. The present work provides a new route for creating ferromagnetism in semiconductors and exploring new p-orbital physics and chemistry. In addition, the material shows elastic-mechanoluminescence that may enable unprecedented mechano-photonic-spintronics.
More Related Videos
11:54Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures
Published on: February 8, 2018
06:49Radio Frequency Magnetron Sputtering of GdBa2Cu3O7âˆ'ÃŽ ´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates
Published on: April 12, 2019
Related Concept Videos
01:31Ferromagnetism
03:51Molecular Orbital Theory II
02:42Valence Bond Theory
02:54Trends in Lattice Energy: Ion Size and Charge
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...