Structural, electronic and magnetic properties of hcp Fe, Co and Ni nanowires encapsulated in zigzag carbon nanotubes

Xie, You; Zhang, J. M.; Huo, Yiping

doi:10.1140/epjb/e2011-10658-4

Cited by 25 publications

(15 citation statements)

References 38 publications

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“…This electronic property is strongly spin dependent due to the spin splitting of Co 3d orbitals [40,41] around the Fermi energy of gold electrodes. This is consistent with the work of Xie et al [17] who found that hybridization between Co 3d and C 2p orbitals for Co nanowires encapsulated in CNTs is strong and results in spin polarization that increases with increasing thickness of the nanowire.…”

supporting

confidence: 93%

Voltage-controlled spin injection with an endohedral fullerene Co@C60 dimer

Saffarzadeh

Kirczenow

2013

Applied Physics Letters

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Spin-dependent transport through an endohedral fullerene Co@C60 dimer with gold electrodes is explored theoretically using density functional and extended Hückel theory. Density of states spin polarizations up to 95%, due to spin-splitting of Co 3d orbitals, are found by varying the gate and/or bias voltage. The current-voltage characteristics and strong (up to 100%) spin polarization of the current indicate that the device can be utilized for highly efficient spin injection into nonmagnetic conductors. This finding opens the way to the realization of electrostatically tuned spintronic nano devices less than 2 nanometers in size, without ferromagnetic electrodes.Carbon-based nanostructures such as fullerenes, carbon nanotubes (CNTs), and graphene, are promising candidates for spintronic applications because of their weak spin-orbit coupling and hyperfine interaction which lead to long spin coherence lengths [1,2]. In particular, the fullerene C 60 molecule is an interesting carbon nanostructure that can be used as a molecular bridge in magnetic tunnel junctions due to its remarkable structural stability and electronic properties [3,4].One way to generate a spin-polarized charge current is to encapsulate magnetic atoms or magnetic nanowires in fullerenes or CNTs [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For example, ab initio calculations showed that Co atoms in CNTs can provide strong spin polarization and considerable magnetic moments [5]. The electrical and magnetic properties of C 60 -Co nanocomposites have also been studied [7,11,12] and tunnel magnetoresistance ratios up to about 30% at low bias voltages were reported, indicating significant spin polarizations [7]. Recent density functional theory (DFT) studies of encapsulated Co atoms in C 60 molecules [18] found hybridization between Co and C 60 orbitals and the most stable structure of Co@C 60 to have the Co atom on top of a hexagonal face. Lu et al. [19] showed that, in the most stable structure of Gd@C 60 , the Gd ion is over a hexagonal ring of the C 60 molecule and the Gd atomic orbitals to hybridize with the C 60 molecular orbitals. Moreover, strong hybridization between the Gd 5d and 6s and carbon orbitals in Gd@C 60 has been observed, both theoretically and experimentally [20].Magnetic atoms encapsulated in carbon nanocages, like the C 60 molecule, are effectively protected against environmental effects such as oxidization, stabilizing the encapsulated magnetic atoms for potential applications for spin injection in nanoscale devices. Accordingly, one can propose magnetic nano junctions to produce high spin-polarized currents with long spin coherence lengths [21]. In this paper we explore theoretically the possibility of such molecular magnetic junctions in which the carbon nanocage is a fullerene dimer. Since, among various types * Author to whom correspondence should be addressed. Electronic mail: asaffarz@sfu.ca of fullerene dimers, C 120 in which the two C 60 molecules are connected by a cyclic C 4 unit, is the simplest one a...

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confidence: 93%

Voltage-controlled spin injection with an endohedral fullerene Co@C60 dimer

Saffarzadeh

Kirczenow

2013

Applied Physics Letters

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“…C1s-ÔÒÇÍÕÓÞ ² ¶¿³ ÐÂÐÑÕÓÖÃÑÍ, ÊÂÒÑÎÐÇÐÐÞØ ÃÓÑÏËAEÑÏ ÔÇÓÇÃÓÂ (Â) [361], ÐÇÊÂÒÑÎÐÇÐÐÞØ ÏÇÕÂÎÎËÚÇÔÍËØ (ÄÇÓØÐââ ÍÓËÄÂâ) Ë ÒÑÎÖÒÓÑÄÑAEÐËÍÑÄÞØ (ÐËÉÐââ ÍÓËÄÂâ)°³¯´(Ã) [434], ÐÂÐÑÕÓÖÃÑÍ, ÊÂÒÑÎÐÇÐÐÞØ ÃÓÑÏËAEÑÏ ÏÇAEË (Ä) [362]. ¬ÓÑÏÇ ÕÑÅÑ, Ä ÎËÕÇÓÂÕÖÓÇ ÒÓËÔÖÕÔÕÄÖáÕ ÓÂÃÑÕÞ, ÒÑ-ÔÄâÜÈÐÐÞÇ ËÔÔÎÇAEÑÄÂÐËá AEÑÐÑÓÐÑÅÑ ÎÇÅËÓÑÄÂÐËâ°³¯Ò ÓË ÄÐÇAEÓÇÐËË Ä ËØ ÍÂÐÂÎÞ ÏÇÕÂÎÎÑÄ: Ti, Zn [446], Co, Ni [447], Fe [446,448,449], Mo [450], Gd [451,452], Eu [451], Cu [453], Ag [454,455] …”

Section: C1smentioning

confidence: 99%

Electronic properties of pristine and modified single-walled carbon nanotubes

Kharlamova¹

2013

Успехи физических наук

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“…Most ab initio calculations of electronic and magnetic properties were conducted for singlewalled carbon NT filled with transition metal nanowires. [13][14][15][16][17][18][19][20][21] Using NTþTM as memory elements for magnetic recording implies sufficient internal anisotropy. However, several experimental magnetization studies 6,12 have shown that NTþTM exhibit superparamagnetic behavior, which is unsuitable for memory elements.…”

Section: Nanostructures At Low Temperaturesmentioning

confidence: 99%

“…Specifically, it is the "zigzag" carbon NT with chiral indices (n,0), that is often used for ab initio calculations. [16][17][18][19] The number of atoms in the unit cell is 4n, and the lattice constant along the translation axis is the same for all the "zigzag" CNTs and equal to 4.26 Å . The lattice constant along the axis of the linear chain of iron atoms (equilibrium interatomic distance) is 2.26-2.25 Å .…”

Section: Nanostructures At Low Temperaturesmentioning

confidence: 99%

Structural, electronic and magnetic properties of chiral nanotubes filled with a linear chain of iron

Boutko

Gusev

Shevtsova

et al. 2014

Low Temperature Physics

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Density-functional calculations of the electronic structure of (n,n/2) chiral carbon nanotubes filled with a linear chain of Fe atoms were conducted for the first time. It was found that upon encapsulating a chain of Fe atoms, the initially semiconducting nanotubes Fe5@(4,2), Fe5@(6,3) and Fe5@(8,4) became metallic. In the case of the Fe5@(8,4) structure, only the iron chain was conductive. All the considered nanotubes maintained large energy of the magnetic anisotropy, which is characteristic for a free linear chain of iron atoms. The magnetic moment on an iron atom was found to vary nonmonotonically with increasing the chiral index n; for the Fe5@(6,3) nanotube, the magnetic moment reached that of a free linear chain of iron atoms.

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Structural, electronic and magnetic properties of hcp Fe, Co and Ni nanowires encapsulated in zigzag carbon nanotubes

Cited by 25 publications

References 38 publications

Voltage-controlled spin injection with an endohedral fullerene Co@C60 dimer

Voltage-controlled spin injection with an endohedral fullerene Co@C60 dimer

Electronic properties of pristine and modified single-walled carbon nanotubes

Structural, electronic and magnetic properties of chiral nanotubes filled with a linear chain of iron

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