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Article

Magnetic Properties of C-Implanted and P-Implanted MgO Single Crystal: A Comparative Experimental and First-Principle Study

by
Xingyu Wang
1,
Chunlin Ma
2,
Weiping Zhou
3 and
Weishi Tan
1,4,*
1
School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
2
School of Physics and Electronic Electrical Engineering, Huaiyin Normal University, Huaian 223001, China
3
School of Materials Science and Engineering, Nanchang University, Nanchang 330031, China
4
All-Solid-State Energy Storage Materials and Devices Key Laboratory of Hunan Province, College of Information and Electronic Engineering, Hunan City University, Yiyang 413002, China
*
Author to whom correspondence should be addressed.
Crystals 2023, 13(3), 386; https://doi.org/10.3390/cryst13030386
Submission received: 26 January 2023 / Revised: 14 February 2023 / Accepted: 21 February 2023 / Published: 23 February 2023
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Abstract

:
The magnetic properties were investigated for C- and P-implanted MgO single crystals, which were irradiated by 80 keV C and P ions with the dose of 3 × 1017 ions/cm2. The magnetic properties of pristine MgO were apparently changed by C and P ion implantation. Room temperature ferromagnetism was presented in the C-implanted sample, while the P-implanted sample only displayed paramagnetism at 20 K. For the purpose of clarifying the correlation between the magnetic properties and microstructure, a comparative study was carried out using experimental and theoretical methods in both C and P ion-implanted samples. The defect types were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence, and absorption spectrum. The existence of intrinsic (Mg vacancies, O vacancies) and extrinsic (C-related and P-related) defects were verified by the experimental results. The magnetic properties induced by various single and composite defects were studied by first-principle calculations. The calculation results indicated that the configuration of VMg (Mg vacancy) + CO (C substitute O defect) was a key factor for the inducing ferromagnetic properties in C-implanted MgO. For the case of the P-implanted MgO, the configuration of P-related defects and intrinsic vacancies can only contribute to the total moment value but cannot induce ferromagnetism.

1. Introduction

Spintronic devices have received significant attention in past decades due to their potential to fabricate faster and more energy-efficient circuits than conventional materials. Magnetic nanoparticles (MNPs) and diluted magnetic semiconductors (DMSs) are two important research directions in the field of spintronics. Many achievements have been obtained in the MNPs domain [1,2,3]. For DMSs, since Dietl et al. [4] revealed the probability of generating room-temperature ferromagnetism (RTFM) in semiconductors by doping transition metal elements, multiple researchers have reported that transition metal-doped semiconductors can hold a Curie temperature (TC) above RTFM [5]. In the case of DMSs, the cations are being partially substituted by transition metal atoms, and plenty of experimental data and theoretical models have confirmed that the ferromagnetism in DMSs originates from the doped atoms [6,7]. Although DMSs have a great prospect in the field of spin-based technology, there are still obstacles to realizing spintronic applications. One of the main issues in dispute is that the magnetism originating from the metal clusters or secondary phases is not appropriate for practical spin-based devices [8], because they will affect the uniformity of spin injection. Apart from that, the stability and repeatability of DMSs for spintronic devices are also problems to be overcome [9]. In order to obtain more suitable spintronic materials, researchers have focused on the non-magnetic elements doped semiconductors. Since the discovery of the unexpected ferromagnetism that was observed in HfO2 films, the d0 ferromagnetic materials tend to be recognized as alternative materials for potential spintronics devices [10]. Moreover, it has been observed that the generating magnetic properties have been generally correlated with defects that can initiate hybridization at the Fermi level and establish long-range ferromagnetism in these systems [11]. Following this idea, researchers have dedicated a great deal of effort to get ferromagnetism in semiconductors above room temperature by doping non-magnetic ions. Xu et al. [12] have reported the presence of ferromagnetic properties in Boron-doped ZnO. Experimental and theoretical results have both indicated that the saturation magnetization of boron-doped ZnO increases with the increasing boron component, and the comprehensive analysis suggested that the induced magnetic moments originated from O 2p states. Ye et al., observed RTFM in C-implanted AlN films. The experimental data revealed the Ms value is proportionate to the dose of implanted C+, and the first-principle calculations demonstrated that the ferromagnetism mainly originated from defect complexes involving interstitial C atoms and Al vacancies [13]. There is also literature [14] proving that the 2p orbital electrons of the carbon atom are the primary source of the induced magnetic moment in C-implanted TiO2. Another report [15] by Hariwal et al., investigated the impact of implanted N ions on the magnetic properties in N-implanted ZnO by varying the implantation angles. The results suggested the concentration of N substituted O defects play a key role in regulating magnetization. However, despite significant achievement gains, discrepancy still persists in these reports and the correlation between the induced ferromagnetism and microstructure still needs to be clarified clearly.
MgO has remarkable properties such as wide band gap, excellent optical properties, and multilevel switching characteristics, which makes it a promising d0 ferromagnetic material for spintronic devices [16]. Owing to this, a substantial amount of experimental and theoretical works have been conducted to explore the origin of ferromagnetism in the MgO system [17]. The synthesis techniques can produce various defects in the materials which invoke changes in their physical and chemical behavior. A consensus has been reached in that the induced ferromagnetism is associated with intrinsic defects or dopant ions in metal oxide semiconductors [18]. Previous research [16] has studied the RTFM in Al-doped MgO nanoparticles, and researchers found that the Ms value increased with the increasing oxygen vacancy concentration. Thus, they concluded that the presence of oxygen vacancies can be used as a mechanism to enhance the localized moments. Conversely, Li et al., demonstrated that the ferromagnetism that was observed in MgO nanoparticles should be attributed to Mg vacancies at the surface [19]. Besides, Rani et al., reported the annealing temperature dependence ferromagnetism and concluded that the ferromagnetism ordering originated from the composite vacancies [20]. Based on the above literatures, we speculate that the type of defect is the key factor to understand the induced ferromagnetism.
Ion implantation is a suitable method to introduce defects with controllable modes in materials, which is usually used to induce unexpected physical phenomena that is caused by defects in materials. Implanting nonmagnetic elements has been verified as an effective way to generate ferromagnetism properties in oxides [14]. Very recently, we have studied the crystalline dependence ferromagnetism in N-implanted MgO [21] and proved that the extrinsic N ions may play a more important role in magnetic properties than intrinsic vacancies. Singh et al. compared Fe+ and Zn+ ion implantation in MgO single crystals and clearly revealed that the induced magnetic behavior resulted from the formation of metal oxides [22]. Accordingly, the comparative study with different implanted ions in MgO is an intuitive method to further elucidate the role of extrinsic defects. Carbon and phosphorus ion implantation are important technologies in semiconductor manufacturing, and both C- and P-ions are acceptor doping particles for MgO. However, the electron distribution and atomic radius of P and C ions have obvious differences, which will result in discrepancy of lattice damage and defect types in the process of implantation. Previous work has demonstrated that C-implanted MgO can generate ferromagnetism properties [23], but the investigation of P-implanted MgO has not been systematically reported.
In this paper, the two non-magnetic ions P and C were selected to be implanted into single MgO crystal and their effect was investigated. For the purpose of comparison, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), absorption spectrum (Abs), and photoluminescence (PL) as practical tools were employed to detect the types and chemical states of the introduced defects in both P-implanted and C-implanted MgO samples. First-principles calculation based on DFT was applied to reveal the possible correlation between the induced ferromagnetism and the defect types and defect configurations.

2. Experiment Details

The MgO single crystals with a thickness of 0.5 mm were purchased from Hefei Kejing Materials Technology Co., Ltd. (Heifei, China) These samples were prepared by the arc melting method and were cut into the size of 10 × 5 mm2. The implantation experiment was conducted at the Institute of Semiconductors, CAS, Beijing, China. The energy of C and P ions were increased to 80 keV in the ion accelerator. The ion injector deviated 7° from the normal direction to minimize the channel effect. The C and P ions were injected into pristine MgO samples to the dose of 3 × 1017 cm−2 at room temperature. The crystal structure of MgO samples were detected by high resolution X-ray diffraction (HRXRD) in Beijing Synchrotron Radiation Facility (BSRF). X-ray electron spectroscopy (XPS, PHI Quantera, Caledonia, IL, USA) was carried out to analyze the element composition and bonding states with monochromatic Al-Kα radiation. The magnetic properties of the samples were measured by a superconducting quantum interference device (SQUID MPMS XL-7, Quantum Design, San Diego, CA, USA) at 5 K, 20 K, and 300 K. The UV-Vis absorption spectra were measured using TU-1901 double beam spectrophotometer at room temperature. The photoluminescence (PL) measurements were carried out at 300 K using a laser diode as an excitation source where the excited wavelength was 370 nm.

3. Results and Discussion

To exclude the ferromagnetism contamination, the XPS measurement was carried out. As displayed in Figure 1a, only the elements Mg, O, C, and Ar were observed in the XPS full spectrum, indicative of the absence of any additional magnetic impurities such as Fe, Co, Ni, etc. The presence of Ar originates from the sample preparation process, and the C is due to the surface contamination. Figure 1b–d shows the magnetic field-dependent magnetization data (M-H) for the pristine, C-implanted, and P-implanted MgO samples recorded at 5 K, 20 K, and room temperature (RT, 300 K). The pristine MgO displays paramagnetic properties at 5 K, and changes into diamagnetic properties at 20 K and 300 K. However, the measurement results show that the C and P ions that were implanted both changed the magnetic properties of the MgO samples. For C-implanted MgO, the samples display ferromagnetic hysteresis loops at both low and room temperatures. The observed magnetic behavior is consistent with the earlier reports on ferromagnetism in C-implanted MgO [23]. In the case of P-implanted MgO, the samples display typical paramagnetic properties at 5 K and 20 K, while they show the diamagnetic properties at room temperature. Apparently, the C-implanted MgO samples had a higher Curie temperature than the P-implanted samples. Although the implantation dose for C and P ions is the same, the C-implanted and P-implanted MgO samples still display different magnetic properties. In our previous studies on neutron irradiation of MgO single crystals [24], the RTFM was not observed. These results indicate that it is almost impossible to introduce stable spin polarization through intrinsic defects in MgO single crystals. Thus, the changed magnetic properties could be attributed to the implanted ions. Usually, several factors could affect the magnetism in the system, including crystallite size, defect types, and their coordination in the lattice structure. A previous report [25] has theoretically investigated the magnetic properties of N-doped MgO and the authors suggested that the presence of doped N ions in the O position is necessary to generate ferromagnetism in the system. Singh et al. also concluded that the coordination of Mg2+ was closely associated with the magnetic behavior through ferromagnetic coupling at RTFM [26]. Therefore, it is essential in this paper to study the defect types and their occupying position of implanted C ions and P ions. The actual result can be made more intuitive by comparing the influence of C ions and P ions on magnetic properties.
High resolution X-ray diffraction (HRXRD) measurements were performed to investigate the effect of C and P ion implantation on the crystal structure. Figure 2 shows the HRXRD results before and after implantation. Both C-implanted and P-implanted MgO samples presented a highly (200) oriented single crystal structure, and no impurity peak or secondary phase appeared. The pristine MgO samples showed high diffraction intensity and narrow full width at half-maximum (FWHM), indicating that it is an ideal single crystal sample. However, for the C and P ion-implanted samples, there is apparently a reduction in diffraction intensity and obviously broadening in FWHM, suggesting that numerous defects are introduced. In addition, a remarkable phenomenon is that the shift of the (100) peak toward a lower angle in both C-implanted and P-implanted samples, which indicates the lattice constant became larger than that of the pristine sample. For P ion implantation, the substitution of P for Mg, O (PMg, PO), or P in the interstitial position (Pint) will cause lattice expansion. For the case of C ion implantation, only when C replaces O (CO) [27] or C is in the interstitial position (Cint), can the lattice be expanded. It is worth noting that the value of the shift angle (0.160°) of the sample after C ion implantation is larger than that (0.139°) of the sample after P ion implantation. This means that the concentration of defects, which can cause lattice expansion in the C-implanted sample, is higher than that in the P-implanted MgO sample.
To further study the element composition and bonding states of the C-implanted and P-implanted samples, XPS measurement for the MgO samples before and after implanting were carried out. For charge referencing, an adventitious C 1s peak located at 284.8 eV was used. Figure 3a–c shows the XPS spectra of Mg 2p of pristine, C-implanted, and P-implanted MgO samples, respectively. For pristine samples, the Mg 2p spectrum shows a symmetrical peak located at 50.8 eV, which should be assigned to the lattice Mg [28]. For the implanted samples, it has been observed that both spectra of Mg 2p showed asymmetry in peak intensity, which suggests that Mg defects were produced due to cascading collisions in the process of implantation. As shown in Figure 3b,c, the Mg 2p spectra can be fitted with two peaks in MgL (50.8 eV) and MgD (51.7 eV). The MgL peak corresponds to the lattice Mg ions, and the MgD peak is related to the Mg vacancies [29]. From Figure 3b,c, it is shown that the MgD relative area of the C-implanted MgO is larger than that of P-implanted MgO, indicating a higher concentration of Mg vacancies in C-implanted samples.
Figure 4a,c shows the spectrum of C 1s of pristine and C-implanted MgO samples. As displayed in Figure 4a, only a single symmetric peak located at 284.8 eV appeared, which is ascribed to C-C bonding states. For the C-implanted sample, the C 1s spectra can be fitted into three peaks located at 283.8 eV (CL), 284.8 eV (C-C), and 287.6 eV (CH), respectively. The peak at 284.8 eV is attributed to C-C bonds (carbon contamination). Pan et al. [30] have reported that C substitute O (CO) can shift the C 1s binding energy to a lower value, thus the peak at 283.8 eV (CL) should be related to the concentration of CO defects. Moreover, Tan et al. [31] investigated the XPS spectrum of carbon-doped ZnO. The results indicate that the C substitute Zn can form O-C-O bonds, which have higher binding energy than that of C-C bonds (284.8 eV). According to these results, we concluded the peak at 287.6 eV (CH) correlated to the CMg (C substitute O site) defects. Noticeably, the relative area of CL is larger than that of CH, suggesting that the concentration of CO type is higher than that of CMg type. Figure 4b,d shows the spectra of P 2p in pristine and P-implanted samples. There is no apparent P 2p signal in pristine sample. In Figure 4d, only a single symmetric peak around 131 eV is observed, which is associated with P-O bonds [32]. These results reveal that the implanted P ions occupy the Mg sites or the interstitial lattice sites in P-implanted MgO. The previous HRXRD results revealed that the defects which can cause lattice expansion dominate in the C-implanted and P-implanted MgO, which is consistent with the XPS results.
The Abs and PL spectrum are effective tools to detect the existence of specific defects, which were usually considered as the source of the inducing magnetic ordering. Figure 5a shows the UV-Vis spectrum of pristine and implanted MgO samples. It can be observed that the absorption spectrum of pristine MgO sample presented no absorption peaks. However, the absorption spectra after C-implantation and P-implantation obviously changed and two absorption peaks, located at about 4.96 eV (250 nm) and 2.60 eV (470) nm in both C-implanted and P-implanted samples. The absorption peak located around 4.96 eV is associated with single anion vacancies (F or F+ center), and the absorption around 2.60 eV can be attributed to the aggregation of F centers [33]. These results indicate the existence of oxygen vacancy in the implanted MgO samples. Noticeably, the intensity of absorption in the P-implanted sample is higher than that in the C-implanted sample, suggesting that the concentration of oxygen vacancies is higher in the P-implanted MgO sample.
Figure 5b shows the PL spectrum of pristine and implanted samples. The excitation wavelength is 370 nm, thus the excited PL bands should be attributed to structural defects rather than band gap emission. The emission intensity and shape of the excited peaks change apparently after implantation, indicating more defects are introduced in the implanted MgO samples. As displayed in Figure 5, the emission peaks located at 414 nm, 437 nm, 455 nm, and 469 nm are observed. According to the literature [34], we attribute the excitation bands at 437 nm and 469 nm to F2+ center, which is originated from 3B1u → 1Ag transitions of F22+ (two F+ centers nearest to each other). The excitation peak that is observed at 414 nm is owing to 2T1u → 2A1g transition F+ (VO with one electron) [35]. In addition, the shoulder peak appeared excited at 455 nm is due to hole trapped at VMg [36]. It is obvious that the emission intensity and integral area of the excited peaks all follow the rule: (C-implanted) > (P-implanted) > (pristine). This means that the concentration of VO and VMg is highest in the C-implanted MgO samples.

4. Frist-Principle Calculations

The Vienna ab-initio Simulation Package was applied on the C-MgO and P-MgO systems to investigate the relationship between the defects and magnetic properties. The Perdew–Burke–Ernzerhof exchange-correlation function was used in the calculation of DOS of states and total energy. A 2 × 2 × 2 supercell with 64 atoms was created to introduce various defects. The schematic structures are shown in Figure 6. The cut off energy was 400 eV. Each optimized structure in the calculation was relaxed until the Hellman–Feynman force was less than 0.01 eV. The density of states was calculated with a 9 × 9 × 9 mesh. In our calculations, we considered all structures with different single and composite defects that most likely exist in the C and P ion-doped MgO systems. The position of doped ions and vacancies are shown in Figure 6. The Mg vacancy (VMg) and O vacancy (VO) are inevitably introduced in MgO in the implantation process, and the magnetic moment is induced by VO and VMg is zero and 1.83 μB, which is in good accordance with the previous calculations [37].
The experimental results reveal the coexistence of various defects. The magnetic moment and total energy of those defects in C-implanted and P-implanted systems are listed in Table 1 and Table 2. For the C-implanted MgO system, the single CO and Cint can give rise to the magnetic moment, while the CMg has no distribution to the magnetic moment. Since the ferromagnetic properties originate from the exchange-correlation of various defects, the magnetic behaviors of composite defects are also explored. Since O vacancy cannot generate magnetic moments, we calculated the total and partial spin-polarized DOS (density of states) and PDOS (partial density of states) of the implanted systems containing one Mg vacancy. The configuration of VMg + CO and VMg + Pint was considered. The TDOS (total density of states) have been displayed in Figure 7. The total-DOS and partial-DOS is obviously asymmetrical; this asymmetry is particularly evident around the Fermi level. We can draw conclusions from the DOS distribution that the dopant ions (C and P) can contribute to the magnetism in all defect configurations. In addition, the oxygen atoms that are situated at neighboring sites of the dopant atom can also give rise to the spin polarization. The incorporation of C and P ions in MgO introduce some new states above the valence band, resulting in the shift in the Fermi level in all the doped systems. According to the Heisenberg exchange model, the exchange effect can make the magnetic moments arrange in a certain direction. If the exchange effect makes magnetic moments parallel in arrangement, the system should show ferromagnetism. On the contrary, the system cannot present ferromagnetic characteristics. For the configurations of Cint + VO, and CO + VO, all the calculated magnetic moments are 1.99 μB and 2.00 μB. The induced magnetic moment by VO is zero, indicating that there is no magnetic coupling in the configurations of Cint + VO and CO + VO. However, the total magnetic moment of CO + VMg is 2.01 μB, which increases slightly in comparison with the single VMg (1.83 μB) and CO (2.00 μB). This means that the spin direction of magnetic moment that is induced by VMg and CO tends to be arranged in parallel. Therefore, we conclude that the ferromagnetic characteristics in C-implanted MgO mainly derive from the configuration of CO + VMg. Meanwhile, the calculations demonstrate the configuration of CO + VMg has the lowest total energy (−365.57 eV) in all the composite defects which can induce magnetic moments. The XRD and XPS experiments have also proven that the CO and Cint play a dominant role in the C-implanted sample, which agrees well with the magnetic measurement results. In the case of the P-implanted MgO system, as listed in Table 2, all of the single defect Pint, PO, and PMg can contribute to the magnetic moment with the value 3.00 μB, 0.99 μB, and 0.78 μB, respectively. But the composite defect Pint + VMg, PO + VMg, and PMg + VMg decrease either the magnetic moment value of Pint or VMg, suggesting that the exchange interaction favors the unpaired electrons in those configurations with anti-parallel spins.
Based on the experimental and theoretical results, the ferromagnetic and paramagnetic signals should attribute to the presence of C or P ions. The magnetic properties can be explained by the bound magnetic polaron model [11]. The experimental results revealed that the C-implanted sample has a higher concentration of intrinsic and extrinsic defects in comparison with the P-implanted sample, and the high defect concentration makes the system reach the threshold of magnetic percolation. Meanwhile, the unpaired electrons in the dominant configuration of VMg + CO can be arranged in parallel directions. Thus, the C-implanted MgO sample showed ferromagnetic characteristics. In the case of the P-implanted sample, although the P-related defects can generate magnetic moments, the asymmetrical anti-parallel spin interaction can decrease the value of magnetic moments, and the polarization energy is too small to resist thermal fluctuation at room temperature. For these reasons, the P-implanted MgO system only displays paramagnetism in an external magnetic field.

5. Conclusions

In conclusion, the C/P ions were implanted into MgO single crystals. We carefully investigated the origin of magnetic properties by using experimental analysis and theoretical calculations. Magnetic measurements revealed that the magnetic properties were changed apparently by the implanted C and P ions. The measurement results of HRXRD and XPS demonstrated the existence of Cint, CO, PMg, Pint, and PO. The Abs and PL results suggested the presence of Mg vacancies and O vacancies in C- and P-implanted samples and demonstrated that the concentration of VO and VMg is higher in the C-implanted MgO samples than P- implanted samples. The first-principle calculations indicated that there is no magnetic coupling in the configurations of Cint + VO and CO + VO. However, the magnetic performance of the VMg + Vo configuration is in accordance with the characteristics of ferromagnetic coupling. Thus, we recognize the configuration VMg + CO should be the main origin of ferromagnetism in C-implanted MgO samples. In contrast with C-implanted MgO sample, the P-implanted MgO systems only shows paramagnetism due to the absence of magnetic coupling effects. This work provides a new method to study the effect of the defects on the magnetic properties and provide a possibility to regulate ferromagnetism.

Author Contributions

Investigation, writing-original draft, X.W. and W.T.; Photoluminescence data measurement, C.M.; Magnetic data measurement, W.Z.; All authors have read and agreed to the published version of the manuscript.

Funding

This work is supported by National Natural Science Foundation of China (Project No.: U1332106, U1832143).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

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Crystals 13 00386 g001 550
Figure 1. (a) Full XPS spectrum of pristine and implanted samples. M-H plots for (b) pristine (c) C-implanted (d) P-implanted MgO samples.
Figure 1. (a) Full XPS spectrum of pristine and implanted samples. M-H plots for (b) pristine (c) C-implanted (d) P-implanted MgO samples.
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Crystals 13 00386 g002 550
Figure 2. HRXRD patterns of pristine, C-implanted and P-implanted MgO samples, obtained using ω-2θ mode. The inset shows the magnification of MgO (200) peaks.
Figure 2. HRXRD patterns of pristine, C-implanted and P-implanted MgO samples, obtained using ω-2θ mode. The inset shows the magnification of MgO (200) peaks.
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Crystals 13 00386 g003 550
Figure 3. XPS core-level spectra of Mg 2p signal for (a) pristine, (b) C-implanted, and (c) P-implanted MgO samples. The black solid lines represent the original XPS data. The red, blue, and pink scatter-lines represent the fitted bonding states.
Figure 3. XPS core-level spectra of Mg 2p signal for (a) pristine, (b) C-implanted, and (c) P-implanted MgO samples. The black solid lines represent the original XPS data. The red, blue, and pink scatter-lines represent the fitted bonding states.
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Crystals 13 00386 g004 550
Figure 4. XPS spectra of (a) C 1s signal and (b) P 2p signal for pristine MgO sample, the black scatter-line represents the original data. (c) XPS spectra of C 1s signal for C-implanted MgO sample. The black scatter line represents the original XPS data. The red, blue, green, and pink scatter-lines represent the fitted bonding states. (d) XPS spectra of P-2p signal for P-implanted MgO sample, the black and red scatter-lines represent the original XPS data and fitted data.
Figure 4. XPS spectra of (a) C 1s signal and (b) P 2p signal for pristine MgO sample, the black scatter-line represents the original data. (c) XPS spectra of C 1s signal for C-implanted MgO sample. The black scatter line represents the original XPS data. The red, blue, green, and pink scatter-lines represent the fitted bonding states. (d) XPS spectra of P-2p signal for P-implanted MgO sample, the black and red scatter-lines represent the original XPS data and fitted data.
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Figure 5. (a) Absorption spectrum and (b) PL spectrum of pristine, C-implanted, and P-implanted MgO samples.
Figure 5. (a) Absorption spectrum and (b) PL spectrum of pristine, C-implanted, and P-implanted MgO samples.
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Figure 6. (a) The position of VMg (CMg), VO (CO), and Cint for the C-implanted MgO system. (b) The position of VMg (PMg), VO (Po), and Pint for the P-implanted system. V represents the Mg vacancy or O vacancy. The CMg and PMg are located at the same position with VMg, the CO and PO are located at the same position with VO.
Figure 6. (a) The position of VMg (CMg), VO (CO), and Cint for the C-implanted MgO system. (b) The position of VMg (PMg), VO (Po), and Pint for the P-implanted system. V represents the Mg vacancy or O vacancy. The CMg and PMg are located at the same position with VMg, the CO and PO are located at the same position with VO.
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Figure 7. Total and partial spin-polarized DOS for the configuration of (a,c) VMg + CO in the C-implanted systems and (b,d) VMg + Pint in the P-implanted systems.
Figure 7. Total and partial spin-polarized DOS for the configuration of (a,c) VMg + CO in the C-implanted systems and (b,d) VMg + Pint in the P-implanted systems.
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Table
Table 1. Magnetic moment of different defect configurations in C-implanted MgO.
Table 1. Magnetic moment of different defect configurations in C-implanted MgO.
TypeCintCOCMgCint + VMgCint + VOCO + VMgCO + VOCMg + VMgCMg + VO
Ms(μB)2.022.000.000.001.992.012.000.000.00
Tot.E−375.76−373.32−374.97−373.61−359.04−365.57−362.25−371.97−365.71
Table
Table 2. Magnetic moment of different defect configurations in P-implanted MgO.
Table 2. Magnetic moment of different defect configurations in P-implanted MgO.
TypePintPOPMgPint + VMgPint + VOPO + VMgPO + VOPMg + VMgPMg + VO
Ms(μB)3.000.990.781.000.970.980.770.991.00
Tot.E−372.58−366.49−373.67−374.62−370.06−374.60−355.31−371.83−362.03
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Wang, X.; Ma, C.; Zhou, W.; Tan, W. Magnetic Properties of C-Implanted and P-Implanted MgO Single Crystal: A Comparative Experimental and First-Principle Study. Crystals 2023, 13, 386. https://doi.org/10.3390/cryst13030386

AMA Style

Wang X, Ma C, Zhou W, Tan W. Magnetic Properties of C-Implanted and P-Implanted MgO Single Crystal: A Comparative Experimental and First-Principle Study. Crystals. 2023; 13(3):386. https://doi.org/10.3390/cryst13030386

Chicago/Turabian Style

Wang, Xingyu, Chunlin Ma, Weiping Zhou, and Weishi Tan. 2023. "Magnetic Properties of C-Implanted and P-Implanted MgO Single Crystal: A Comparative Experimental and First-Principle Study" Crystals 13, no. 3: 386. https://doi.org/10.3390/cryst13030386

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