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Liu C, Hübner R, Xie Y, Wang M, Xu C, Jiang Z, Yuan Y, Li X, Yang J, Li L, Weschke E, Prucnal S, Helm M, Zhou S. Ultra-fast annealing manipulated spinodal nano-decomposition in Mn-implanted Ge. NANOTECHNOLOGY 2019; 30:054001. [PMID: 30499464 DOI: 10.1088/1361-6528/aaefb1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the present work, millisecond-range flash lamp annealing is used to recrystallize Mn-implanted Ge. Through systematic investigations of structural and magnetic properties, we find that the flash lamp annealing produces a phase mixture consisting of spinodally decomposed Mn-rich ferromagnetic clusters within a paramagnetic-like matrix with randomly distributed Mn atoms. Increasing the annealing energy density from 46, via 50, to 56 J cm-2 causes the segregation of Mn atoms into clusters, as proven by transmission electron microscopy analysis and quantitatively confirmed by magnetization measurements. According to x-ray absorption spectroscopy, the dilute Mn ions within Ge are in d 5 electronic configuration. This Mn-doped Ge shows paramagnetism, as evidenced by the unsaturated magnetic-field-dependent x-ray magnetic circular dichroism signal. Our study reveals how spinodal decomposition occurs and influences the formation of ferromagnetic Mn-rich Ge-Mn nanoclusters.
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Affiliation(s)
- Chaoming Liu
- Harbin Institute of Technology, School of Materials Science and Engineering, 150001, Harbin, People's Republic of China. Laboratory for Space Environment and Physical Science, Research Center of Basic Space Science, Harbin Institute of Technology, 150001, Harbin, People's Republic of China. Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden, Germany
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Yuan Y, Wang M, Xu C, Hübner R, Böttger R, Jakiela R, Helm M, Sawicki M, Zhou S. Electronic phase separation in insulating (Ga, Mn) As with low compensation: super-paramagnetism and hopping conduction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:095801. [PMID: 29355839 DOI: 10.1088/1361-648x/aaa9a7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In the present work, low compensated insulating (Ga,Mn)As with 0.7% Mn is obtained by ion implantation combined with pulsed laser melting. The sample shows variable-range hopping transport behavior with a Coulomb gap in the vicinity of the Fermi energy, and the activation energy is reduced by an external magnetic field. A blocking super-paramagnetism is observed rather than ferromagnetism. Below the blocking temperature, the sample exhibits a colossal negative magnetoresistance. Our studies confirm that the disorder-induced electronic phase separation occurs in (Ga,Mn)As samples with a Mn concentration in the insulator-metal transition regime, and it can account for the observed superparamagnetism and the colossal magnetoresistance.
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Affiliation(s)
- Ye Yuan
- Helmholtz-Zentrum Dresden Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden, Germany. Technische Universität Dresden, D-01062 Dresden, Germany
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Laref A, AlMudlej A, Laref S, Yang JT, Xiong YC, Luo SJ. Ab-Initio Investigations of Magnetic Properties and Induced Half-Metallicity in Ga 1-xMn xP (x = 0.03, 0.25, 0.5, and 0.75) Alloys. MATERIALS (BASEL, SWITZERLAND) 2017; 10:ma10070766. [PMID: 28773127 PMCID: PMC5551809 DOI: 10.3390/ma10070766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 06/29/2017] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
Ab-initio calculations are performed to examine the electronic structures and magnetic properties of spin-polarized Ga1-xMnxP (x = 0.03, 0.25, 0.5, and 0.75) ternary alloys. In order to perceive viable half-metallic (HM) states and unprecedented diluted magnetic semiconductors (DMSs) such as spintronic materials, the full potential linearized augmented plane wave method is utilized within the generalized gradient approximation (GGA). In order to tackle the correlation effects on 3d states of Mn atoms, we also employ the Hubbard U (GGA + U) technique to compute the magnetic properties of an Mn-doped GaP compound. We discuss the emerged global magnetic moments and the robustness of half-metallicity by varying the Mn composition in the GaP compound. Using GGA + U, the results of the density of states demonstrate that the incorporation of Mn develops a half-metallic state in the GaP compound with an engendered band gap at the Fermi level (EF) in the spin-down state. Accordingly, the half-metallic feature is produced through the hybridization of Mn-d and P-p orbitals. However, the half-metallic character is present at a low x composition with the GGA procedure. The produced magnetic state occurs in these materials, which is a consequence of the exchange interactions between the Mn-element and the host GaP system. For the considered alloys, we estimated the X-ray absorption spectra at the K edge of Mn. A thorough clarification of the pre-edge peaks is provided via the results of the theoretical absorption spectra. It is inferred that the valence state of Mn in Ga1-xMnxP alloys is +3. The predicted theoretical determinations surmise that the Mn-incorporated GaP semiconductor could inevitably be employed in spintronic devices.
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Affiliation(s)
- Amel Laref
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
- Department of Physics, National Taiwan University, Taipei 106, Taiwan.
| | - Abeer AlMudlej
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Slimane Laref
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Str., D-35032 Marburg, Germany.
| | - Jun Tao Yang
- School of Science, Hubei University of Automotive Technology (HUAT), Shiyan 442002, Hubei, China.
| | - Yong-Chen Xiong
- School of Science, Hubei University of Automotive Technology (HUAT), Shiyan 442002, Hubei, China.
| | - Shi Jun Luo
- School of Science, Hubei University of Automotive Technology (HUAT), Shiyan 442002, Hubei, China.
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Yuan Y, Hübner R, Liu F, Sawicki M, Gordan O, Salvan G, Zahn DRT, Banerjee D, Baehtz C, Helm M, Zhou S. Ferromagnetic Mn-Implanted GaP: Microstructures vs Magnetic Properties. ACS APPLIED MATERIALS & INTERFACES 2016; 8:3912-3918. [PMID: 26799492 DOI: 10.1021/acsami.5b10949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ferromagnetic GaMnP layers were prepared by ion implantation and pulsed laser annealing (PLA). We present a systematic investigation on the evolution of microstructure and magnetic properties depending on the pulsed laser annealing energy. The sample microstructure was analyzed by high-resolution X-ray diffraction (HR-XRD), transmission electron microscopy (TEM), Rutherford backscattering spectrometry (RBS), ultraviolet Raman spectroscopy (UV-RS), and extended X-ray absorption fine structure (EXAFS) spectroscopy. The presence of X-ray Pendellösung fringes around GaP (004) and RBS channeling prove the epitaxial structure of the GaMnP layer annealed at the optimized laser energy density (0.40 J/cm(2)). However, a forbidden TO vibrational mode of GaP appears and increases with annealing energy, suggesting the formation of defective domains inside the layer. These domains mainly appear in the sample surface region and extend to almost the whole layer with increasing annealing energy. The reduction of the Curie temperature (TC) and of the uniaxial magnetic anisotropy gradually happens when more defects and the domains appear as increasing the annealing energy density. This fact univocally points to the decisive role of the PLA parameters on the resulting magnetic characteristics in the processed layers, which eventually determine the magnetic (or spintronics) figure of merit.
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Affiliation(s)
- Ye Yuan
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
- Technische Universität Dresden , D-01062 Dresden, Germany
| | - René Hübner
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
| | - Fang Liu
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
- Technische Universität Dresden , D-01062 Dresden, Germany
| | - Maciej Sawicki
- Institute of Physics, Polish Academy of Sciences , al. Lotników 32/46, PL-02 668 Warszawa, Poland
| | - Ovidiu Gordan
- Institute of Physics, Chemnitz University of Technology , 09107 Chemnitz, Germany
| | - G Salvan
- Institute of Physics, Chemnitz University of Technology , 09107 Chemnitz, Germany
| | - D R T Zahn
- Institute of Physics, Chemnitz University of Technology , 09107 Chemnitz, Germany
| | - D Banerjee
- Dutch-Belgian Beamline (DUBBLE), ESRF - The European Synchrotron , CS 40220, 38043 Grenoble, France
| | - Carsten Baehtz
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
| | - Manfred Helm
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
- Technische Universität Dresden , D-01062 Dresden, Germany
| | - Shengqiang Zhou
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden Rossendorf , Bautzner Landstrasse 400, D-01328 Dresden, Germany
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Park YH, Ha R, Park TE, Kim SW, Seo D, Choi HJ. Magnetic In x Ga 1 - x N nanowires at room temperature using Cu dopant and annealing. NANOSCALE RESEARCH LETTERS 2015; 10:2501. [PMID: 26055472 PMCID: PMC4493842 DOI: 10.1186/1556-276x-10-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/11/2014] [Indexed: 06/04/2023]
Abstract
Single-crystal, Cu-doped In x Ga1 - x N nanowires were grown on GaN/Al2O3 substrates via a vapor-liquid-solid (VLS) mechanism using Ni/Au bi-catalysts. The typical diameter of the Cu:In x Ga1 - x N nanowires was 80 to 150 nm, with a typical length of hundreds of micrometers. The as-grown nanowires exhibited diamagnetism. After annealing, the nanowires exhibited ferromagnetism with saturation magnetic moments higher than 0.8 μB (1 μB × 10(-24) Am(2)) per Cu atom at room temperature by the measurements using a superconducting quantum interference device (SQUID) magnetometer. X-ray absorption and X-ray magnetic circular dichroism spectra at Cu L 2,3-edges indicated that the doped Cu had a local magnetic moment and that its electronic configuration was mainly 3d (9). It possessed a small trivalent component, and thus, the n-type behavior of electrical property is measured at room temperature.
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Affiliation(s)
- Youn Ho Park
- />Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Ryong Ha
- />Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Tea-Eon Park
- />Spin Convergence Research Center, Korea Institute of Science and Technology (KIST), Seoul, 136-791 Republic of Korea
| | - Sung Wook Kim
- />Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Dongjea Seo
- />Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Heon-Jin Choi
- />Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
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Dietl T. A ten-year perspective on dilute magnetic semiconductors and oxides. NATURE MATERIALS 2010; 9:965-74. [PMID: 21102516 DOI: 10.1038/nmat2898] [Citation(s) in RCA: 295] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Over the past ten years, the search for compounds combining the properties of semiconductors and ferromagnets has evolved into an important field of materials science. This endeavour has been fuelled by many demonstrations of remarkable low-temperature functionalities in the ferromagnetic structures (Ga,Mn)As and p-(Cd,Mn)Te, and related compounds, and by the theoretical prediction that magnetically doped, p-type nitride and oxide semiconductors might support ferromagnetism mediated by valence-band holes to above room temperature. Indeed, ferromagnetic signatures persisting at high temperatures have been detected in a number of non-metallic systems, even under conditions in which the presence of spin ordering was not originally anticipated. Here I review recent experimental and theoretical developments, emphasizing that they not only disentangle many controversies and puzzles accumulated over the past decade but also offer new research prospects.
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Affiliation(s)
- Tomasz Dietl
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02-668 Warszawa, Poland.
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Zhou S, Schmidt H. Mn-doped Ge and Si: A Review of the Experimental Status. MATERIALS 2010; 3:5054-5082. [PMID: 28883369 PMCID: PMC5445810 DOI: 10.3390/ma3125054] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/16/2010] [Accepted: 11/19/2010] [Indexed: 11/16/2022]
Abstract
Diluted ferromagnetic semiconductors (FMS) are in the focus of intense research due to their potential applications in spintronics and their striking new physical properties. So far Mn-doped III-V compound semiconductors such as GaMnAs are the most important and best understood ones, but they are ferromagnetic only at well below room temperature. An interesting alternative could be magnetic semiconductors based on elemental semiconductors, also owing to their compatibility with Si microelectronics. In the last decades, considerable amount of work has been devoted to fabricate Mn-doped Ge and Si FMS. In this article, the structural, magnetic and magneto-transport properties of Mn-doped Ge and Si will be reviewed.
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Affiliation(s)
- Shengqiang Zhou
- Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
| | - Heidemarie Schmidt
- Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
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Stone PR, Alberi K, Tardif SKZ, Beeman JW, Yu KM, Walukiewicz W, Dubon OD. Metal-insulator transition by isovalent anion substitution in Ga1-xMnxAs: implications to ferromagnetism. PHYSICAL REVIEW LETTERS 2008; 101:087203. [PMID: 18764655 DOI: 10.1103/physrevlett.101.087203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Indexed: 05/26/2023]
Abstract
We have investigated the effect of partial isovalent anion substitution in Ga1-xMnxAs on electrical transport and ferromagnetism. Substitution of only 2.4% of As by P induces a metal-insulator transition at a constant Mn doping of x=0.046 while the replacement of 0.4% As with N results in the crossover from metal to insulator for x=0.037. This remarkable behavior is consistent with a scenario in which holes located within an impurity band are scattered by alloy disorder in the anion sublattice. The shorter mean free path of holes, which mediate ferromagnetism, reduces the Curie temperature T_{C} from 113 to 60 K (100 to 65 K) upon the introduction of 3.1% P (1% N) into the As sublattice.
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Affiliation(s)
- P R Stone
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, USA.
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Seong HK, Kim JY, Kim JJ, Lee SC, Kim SR, Kim U, Park TE, Choi HJ. Room-temperature ferromagnetism in Cu doped GaN nanowires. NANO LETTERS 2007; 7:3366-71. [PMID: 17902723 DOI: 10.1021/nl0716552] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We report magnetism in Cu doped single-crystalline GaN nanowires. The typical diameter and the length of the Ga1-xCuxN nanowires (x = 0.01, 0.024) are 10-100 nm and tens of micrometers, respectively. The saturation magnetic moments are measured to be higher than 0.86 microB/Cu at 300 K, and the Curie temperatures are far above room temperature. Anomalous X-ray scattering and X-ray diffraction measurement make it clear that Cu atoms substitute the Ga sites, and they largely take part in the wurtzite network of host GaN. X-ray absorption and X-ray magnetic circular dichroism spectra at Cu L(2,3) edges show that doped Cu has local magnetic moment and the electronic configuration of it is mainly 3d9 but mixed with a small portion of trivalent component. It seems that the ionocovalent bonding nature of Cu 3d orbital with surrounding semiconductor medium makes Cu atom a mixed electron configuration and local magnetic moments. These outcomes suggest that the Ga1-xCuxN system is a room-temperature ferromagnetic semiconductor.
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Affiliation(s)
- Han-Kyu Seong
- Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea
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Yildirim Y, Alvarez G, Moreo A, Dagotto E. Large-scale Monte Carlo study of a realistic lattice model for Ga(1-x)MnxAs. PHYSICAL REVIEW LETTERS 2007; 99:057207. [PMID: 17930788 DOI: 10.1103/physrevlett.99.057207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 02/09/2007] [Indexed: 05/25/2023]
Abstract
Mn-doped GaAs is studied with a real-space Hamiltonian on an fcc lattice that reproduces the valence bands of undoped GaAs. Large-scale Monte Carlo (MC) simulations on a Cray XT3, using up to a thousand nodes, were needed. Spin-orbit interaction and the random distribution of the Mn ions are considered. The hopping amplitudes are functions of the GaAs Luttinger parameters. At the realistic coupling J approximately 1.2 eV the MC Curie temperature and magnetization curves agree with experiments for x = 8.5% annealed samples. Mn-doped GaSb and GaP are also briefly discussed.
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Affiliation(s)
- Yucel Yildirim
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37966-1200, USA
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