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Compared with conventional semiconductors, the diluted magnetic semiconductors, in which the cations are substituted by transition metal ions, have attracted a great deal of attention due to their promising applications in spintronics. Recently, the unexpected room temperature ferromagnetism has been found in many undoped oxides. These findings cha...
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Dilute magnetic semiconductors (DMS), achieved through substitutional doping of spin‐polarized transition metals into semiconducting systems, enable experimental modulation of spin dynamics in ways that hold great promise for novel magneto–electric or magneto–optical devices, especially for two‐dimensional (2D) systems such as transition metal dich...
The dilute magnetic properties of materials have important potential applications in the field of electronic science and technology. Intrinsic Ca2Ge is a new environmentally friendly semiconductor material, and exhibits cubic and orthorhombic phases. The crystal structure characteristics of Ca2Ge indicate that the modulation of its dilute magnetic...
Using first-principles calculations, we have studied the energetic feasibility and magnetic properties of transition metal (TM) doped PtSe2 monolayers. Our study shows that TM doped PtSe2 layers with 6.25% doping exhibit versatile spintronic behaviour depending on the nature of the dopant TM atoms. Groups IVB and VIII10 TM doped PtSe2 layers are no...
Based on the first-principles calculations, we investigate the structural, electronic, and magnetic properties of defects in monolayer SnS. We study the formation and migration of vacancies at both Sn- and S-sites. In comparison to the S-site vacancy, our calculations show that creating a vacancy at the Sn-site requires lesser energy, indicating th...
![Plot of (αhv)1/2vs.hv\documentclass[12pt]{minimal} \usepackage{amsmath}...](publication/350694983/figure/fig4/AS:1010193802477569@1617860379523/Plot-of-ahv1-2vshvdocumentclass12ptminimal-usepackageamsmath_Q320.jpg)
We report the experimental observation of and theoretical explanation for the reduction of dopant ions and enhancement of magnetic properties in Ce-doped TiO 2 diluted magnetic semiconductors from UV-light irradiation. Substantial increase in Ce ³⁺ concentration and creation of oxygen vacancy defects in the sample due to UV-light irradiation was ob...
Citations
... To obtain practical ferromagnetic (FM) semiconductors, researchers have performed numerous works. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] One of the materials in focus is the wide-band-gap (3.05 eV) and versatile semiconductor TiO 2 , [15][16][17][18][19][20][21] in which some of Ti can be substituted by magnetic transition metal (TM) ions to yield a solid solution. Sato et al. and Fukushima et al. reported that the spinodal decomposition phase in dilute magnetic semiconductors offers the possibility to have high Curie temperatures (T C ). 22,23) Matsumoto et al. fabricated Co-doped TiO 2 films with higher T C by pulsed laser deposition (PLD) in 2001. ...
... where k B is the Boltzmann constant. Using this equation, we estimated a T C of 1151 K for S (12). Comparing S(12) with S(13), we observed that the FM coupling intensity decreases with increasing distance between two Cu@Ti ions. ...
... The value U = 2.5 eV, which is comparable to values in other works, was used in the calculation. 53) It was found that FM states are also 37 meV, which is more stable than the AFM ordering for the configuration S (12). Therefore, the strong FM coupling is reasonable. ...
The electronic structures and magnetic properties of Cu-doped anatase TiO2 have been investigated by first-principles calculations based on the density functional theory (DFT). Calculation results indicated that one Cu-substituted Ti ([email protected]) defect can introduce a total magnetic moment of 1 μB, which mainly distributed on the doped Cu atom and six neighboring oxygen atoms. In accordance with the group theory, the fivefold Cu-3d energy level splits into one threefold t2g orbital and one twofold eg orbital under the octahedral crystal field formed by the six neighboring oxygen atoms. The asymmetric electron occupation of the eg orbital generates a magnetic moment. The magnetic coupling between such two [email protected] defects is ferromagnetic, and the ferromagnetic energy advantage is 149 meV compared with the antiferromagnetic one. The larger energy difference means that the ferromagnetic coupling between the [email protected] defects is stable even at room temperature. The origin of ferromagnetism can be explained using the double-exchange model.
We have carried out first-principle spin-polarized calculations to investigate the electronic structures and the magnetic properties of Cu-doped wurtzite ZnO. It was found that the CuZn substitution can introduce 1 μB local magnetic moment into the doped system, whereas the ferromagnetic coupling between CuZns is so weak that the system cannot keep ferromagnetism at higher temperature. In Zn vacancy (VZn) and CuZn coexisted system, Cu is in the Cu ²⁺/Cu ³⁺ mixed valence under the influence of acceptor defect VZn. Cu-3d electrons couple with O(around VZn)-sp electrons and then form Cu²⁺ −VZn −Cu²⁺ or Cu²⁺ −VZn−−Cu³⁺ bound magnetic polaron (BMP) in the range of 1.27 ∼ 1.90 nm. The overlapping between BMPs is the main ferromagnetism origin of ZnO/Cu. According to our analysis, we thought that ZnO/Cu system will display stronger ferromagnetism when the Cu concentration attains 3% in atomic percentage. The calculated results and analysis will shed light on the origin of ferromagnetism in ZnO/Cu.
