Behavior of precipitates in GaMnN

Lee, K. J.; Yu, Fucheng; Kim, J. A.; Kim, D. J.; Kim, B. G.; Kang, Y.M.; Kim, H. J.; Ihm, Young Eon

doi:10.1002/pssb.200304534

Cited by 14 publications

(9 citation statements)

References 9 publications

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“…Recently, a similar behavior has been observed in an antiperovskite compound GaNMn 3 by Song et al [33]. A variety of magnetic behavior has been reported for GaNMn 3 in the prior literatures [34][35][36][37][38][39]. Song et al attribute these differences to the differences in the various synthesis routes employed for this compound and the resulting variation in compositions.…”

Section: Electronic and Magnetic Properties Of Innmmentioning

confidence: 53%

Preparation and properties of antiperovskite-type nitrides: InNNi3 and InNCo3

Cao

Liao

et al. 2009

Journal of Solid State Chemistry

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Section: Electronic and Magnetic Properties Of Innmmentioning

confidence: 53%

Preparation and properties of antiperovskite-type nitrides: InNNi3 and InNCo3

Cao

Liao

et al. 2009

Journal of Solid State Chemistry

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“…17 Alternatively, some experimental results show antiferromagnetic ͑AFM͒ coupling between Mn ions at T =2 K ͑Refs. 20-22͒ and others show a FM phase with the existence of secondary phases [23][24][25][26][27] or without secondary phases 12,13,16,[28][29][30][31][32] within the detection limits. Very recently, the intrinsic ferromagnetism in wurtzite Mn:GaN was demonstrated with a rather large magnetic moment of 2.4 B / Mn, but the T C is only about 8 K for the concentration of 6.8% sample.…”

Section: Introductionmentioning

confidence: 99%

Neutral and charged embedded clusters of Mn in doped GaN from first principles

et al. 2007

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Based on extensive density-functional theory calculations, the spatial distribution and magnetic coupling of Mn atoms in Mn:GaN have been reinvestigated by doping up to five Mn atoms in large supercells, where the formation energies and the electronic structure for both the neutral and charged valence states are studied. The doped Mn atoms have a strong tendency to form substitutional Mn-N-Mn bonded embedded clusters with short-range magnetic interactions, where the long-range wurtzite structure is maintained. While for neutral pair doping the coupling is ferromagnetic regardless of the distance and orientation of the Mn atoms, the negatively charged states tend to weaken the parallel coupling. Significantly, for larger ͑than pair͒ cluster configurations for both neutral and all the energetically favorable charged states, states containing antiparallel coupling are always favored. Thus, we argue that the "giant cluster moment" in Mn:GaN, as proposed by Rao and Jena based on study of free clusters ͓Phys. Rev. Lett. 89, 185504 ͑2002͔͒ and calculated by Sandratskii et al. ͓Phys. Rev. B 71, 045210 ͑2005͔͒, is not applicable for "larger" ͑Ͼ2͒ Mn-cluster-doped GaN. The size of the supercells employed and the atomic relaxation are found crucial for an accurate description, and are partially responsible for these discrepancies. Also important is that the electrical conductivity of Mn:GaN depends sensitively on the valence states, where the negatively charged state Mn 2+ ͑d 5 ͒ exhibits highly insulating character as observed in experiments. The formation of embedded clustering leads to a strong local structural distortion and a significant spin polarization on neighboring N atoms due to hybridization of Mn 3d and N 2p orbitals. Our results highlight the intrinsically complex nature of the spatial distribution and magnetism in transition metal doped dilute magnetic semiconductors, and can rationalize some hitherto puzzling experimental observations, notably the low saturation moments, the contracted lattice constants, and the highly insulating behavior.

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“…[21][22][23][24] A high Mn concentration in GaN films is predicted to be necessary for ferromagnetism to persist above room temperature, 1 but experimental studies on films with x Ͼ 5 at. % Mn often reveal Mn clustering [25][26][27] or secondary phases such as ferrimagnetic Mn 4 N ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Single phase nanocrystalline GaMnN thin films with high Mn content

Granville

Budde

Ruck

et al. 2006

Journal of Applied Physics

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Ga 1 − x Mn x N thin films with a Mn content as high as x=0.18 have been grown using ion-assisted deposition and a combination of Rutherford backscattering spectroscopy and nuclear reaction analysis was used to determine their composition. The structure of the films was determined from x-ray diffraction, transmission electron microscopy, and extended x-ray absorption fine structure (EXAFS). The films are comprised of nanocrystals of random stacked GaMnN and there is no evidence of Mn-rich secondary phases or clusters. EXAFS measurements at the Mn and Ga edge are almost identical to those at the Ga edge from Mn-free nanocrystalline GaN films, showing that the Mn occupies the Ga lattice sites, and simulated radial distribution functions of possible Mn-rich impurity phases bear no resemblance to the experimental data. The results indicate that these are the most heavily Mn-doped single phase GaN films studied to date.

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Behavior of precipitates in GaMnN

Cited by 14 publications

References 9 publications

Preparation and properties of antiperovskite-type nitrides: InNNi3 and InNCo3

Preparation and properties of antiperovskite-type nitrides: InNNi3 and InNCo3

Neutral and charged embedded clusters of Mn in doped GaN from first principles

Single phase nanocrystalline GaMnN thin films with high Mn content

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