Room temperature ferromagnetic properties of (Ga, Mn)N

El‐Masry, N. A.; Stadelmaier, H. H.; Ritums, M. K.; Reed, Meredith; Parker, C. A.; Roberts, John C.; Bedair, S. M.

doi:10.1063/1.1419231

Cited by 676 publications

(382 citation statements)

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“…The relatively large effective exchange parameter for [V(Bz)] ∞ and [Mn(Bz)] ∞ is due to the DE mechanism, which usually lead to FM with a relatively high Curie temperature, e.g. the relative high Curie temperature (about 228-370 K) [29] for Mn doped GaN is due to the DE mechanism [23,30].…”

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confidence: 99%

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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We investigate the electronic and magnetic properties of the proposed one-dimensional transition metal (TM=Sc, Ti, V, Cr, and Mn) -benzene (Bz) sandwich polymers by means of density functional calculations. [V(Bz)]∞ is found to be a quasi-half-metallic ferromagnet and half-metallic ferromagnetism is predicted for [Mn(Bz)]∞. Moreover, we show that stretching the [TM(Bz)]∞ polymers could have dramatic effects on their electronic and magnetic properties. The elongated [V(Bz)]∞ displays half-metallic behavior, and [Mn(Bz)]∞ stretched to a certain degree becomes an antiferromagnetic insulator. The possibilities to stabilize the ferromagnetic order in [V(Bz)]∞ and [Mn(Bz)]∞ polymers at finite temperature are discussed. We suggest that the hexagonal bundles composed by these polymers might display intrachain ferromagnetic order at finite temperature by introducing interchain exchange coupling.PACS numbers: 71.20.Rv, 75.75.+a, 82.35.Lr It is expected that the new generation of devices will exploit spin dependent effects, what has been called spintronics [1,2]. A challenge now facing spintronics is transmitting spin signals over long enough distances to allow for spin manipulation. An ideal device for spin-polarized transport should have several key ingredients. First, it should work well at room temperature and should offer as high a magnetoresistance (MR) ratio as possible. In this sense, a half-metallic (HM) ferromagnet with the Curie temperature higher than room temperature is highly desirable since there would be only one electronic spin channel at the Fermi energy [3]. Second, the size or diameter of the materials should be uniform for large scale applications. Carbon nanotubes (CNTs) were considered as promising one-dimensional (1D) spin mediators because of their ballistic nature of conduction and relatively long spin scattering length (at least 130 nm) [4,5]. Coherent spin transport has been observed in multiwalled CNT systems with Co electrodes. The maximum MR ratio of 9% was observed in multiwalled CNTs at 4.2 K. However, as the temperature increases to 20 K, the MR ratio goes to zero, preventing any room temperature applications [4]. A theoretical work suggested that the ferromagnetic (FM) transition-metal (TM) /CNT hybrid structures may be used as devices for spin-polarized transport to further increase the MR ratio [6]. Unfortunately, although large spin polarization is found in these systems, there is no HM behavior. Another difficulty with CNT is that the devices are unlikely to be very reproducible due to the wide assortment of tube size and helicity that is produced during synthesis. Wide variation in device behavior was reported in the CNT experiment [4].Recently, an experimental study suggested that the unpaired electrons on the metal atoms couple ferromagnetically in the multidecker organometallic sandwich Vbenzene (Bz) complexes, i.e., V n (Bz) n+1 clusters [7]. The FM sandwich clusters are supposed to serve as nanomagnetic building blocks in applications such as recording media or spintronic de...

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One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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“…Over the past decade, scientists and engineers around the world have shown significant interest in the investigations of metallic nitrides (e.g., GaN, AlN, InN, CrN, TiN [1][2][3][4][5][6][7]) with dopants such as Si [1], Al [8], Mn, C [8] and Cr [4][5][6][7] owing to their unique properties, e.g. large band-gap [2][3][9][10][11], high surface acoustic velocity [2], corrosion resistance [2], oxidation resistance [12], excellent chemical and thermal stability as well as mechanical robustness [13].…”

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confidence: 99%

Near-edge X-ray absorption fine structure studies of Cr1−xMxN coatings

Rahman

Duan

Jiang

et al. 2013

Journal of Alloys and Compounds

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Near-edge X-ray absorption fine structure studies of Cr 1-x M x N coatings, (2013), doi: http://dx.doi.org/10. 1016/ j.jallcom.2013.06.021 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractCr 1-x M x N coatings, with doping concentrations (Si or Al) varying from 14.3 to 28.5 at.%, were prepared on AISI M2 tool steel substrates using a TEER UDP 650/4 closed field unbalanced magnetron sputtering system. Near-edge X-ray absorption fine structure (NEXAFS) characterization was carried out to measure the aluminum and silicon Kedges, as well as chromium L-edge, in the coatings. Two soft X-ray techniques, Auger electron yield (AEY) and total fluorescence yield (TFY), were employed to investigate the surface and inner structural properties of the materials in order to understand the structural evolution of CrN matrix with addition of Al (or Si) elements. Investigations on the local bonding states and grain boundaries of the coatings, using NEXAFS technique, provide significant information which facilitates understanding of the local electronic 2 structure of the atoms and shed light on the origins of the high mechanical strength and oxidation resistance of these technologically important coatings.

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“…Following the successful development of Ga 1−x Mn x As 3,4,5 and In 1−x Mn x As 6 as ferromagnetic semiconductors (with x ≈ 1 − 10%) using careful low-temperature molecular beam epitaxy (MBE) technique, intensive worldwide activity has led to claims of ferromagnetism (some at room temperatures and above) in several magnetically doped semiconductors, e.g. GaMnP, 7 GaMnN, 8 GeMn, 9 GaMnSb. 10 It is at present unclear whether all these reports of ferromagnetism (particularly at room temperatures or above) are indeed intrinsic magnetic behavior or are arising from clustering and segregation effects associated with various Mn-complexes (which have low solubility) and related materials problems.…”

Section: Introductionmentioning

confidence: 99%

How to make semiconductors ferromagnetic: a first course on spintronics

Sarma

Hwang

Kaminski

2003

Solid State Communications

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The rapidly developing field of ferromagnetism in diluted magnetic semiconductors, where a semiconductor host is magnetically doped by transition metal impurities to produce a ferromagnetic semiconductor (e.g. Ga1−xMnxAs with x ≈ 1 − 10%), is discussed with the emphasis on elucidating the physical mechanisms underlying the magnetic properties. Recent key developments are summarized with critical discussions of the roles of disorder, localization, band structure, defects, and the choice of materials in producing good magnetic quality and high Curie temperature. The correlation between magnetic and transport properties is argued to be a crucial ingredient in developing a full understanding of the properties of ferromagnetic semiconductors.

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Room temperature ferromagnetic properties of (Ga, Mn)N

Cited by 676 publications

References 6 publications

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

Near-edge X-ray absorption fine structure studies of Cr1−xMxN coatings

How to make semiconductors ferromagnetic: a first course on spintronics

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