Magnetic characteristics of nanocrystalline GaMnN films deposited by reactive sputtering

Leite, Douglas Marcel Gonçalves; Pereira, Aledir Silveira; Iwamoto, W.; Pagliuso, P. G.; Lisboa‐Filho, Paulo Noronha; Silva, J.H.D. da

doi:10.1016/j.solidstatesciences.2012.11.020

Cited by 2 publications

(1 citation statement)

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“…Since Dietl et al proposed that GaN and ZnO doped with magnetic impurities at low concentration can exhibit ferromagnetism at room temperature, 5 several authors have reported evidence of this property using Mn as a magnetic impurity in GaN. [6][7][8][9] However, the origin of ferromagnetism in GaN and other dilute magnetic semiconductors (DMS) is not clear because conventional super-exchange or double-exchange interactions do not adequately explain the long-range magnetic order observed for magnetic impurities at low concentrations. [10][11][12][13] Some reports have proposed that ferromagnetism in DMS is generated by exchange interactions mediated by the pointdefects present in semiconductors; consequently, much effort has been devoted to achieving precise control in point-defect generation during the synthesis of GaN:Mn.…”

Section: Introductionmentioning

confidence: 99%

Influence of Ga vacancies, Mn and O impurities on the ferromagnetic properties of GaN micro- and nanostructures

Guzmán

Escudero

Silva

et al. 2018

Journal of Applied Physics

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We present a study of the influence of gallium vacancy (V Ga) point defects on the ferromagnetic properties of GaN:Mn and GaN:Mn,O micro-and nanostructures. Results demonstrate that the generation of these point defects enhances the ferromagnetic signal of GaN:Mn microstructures, while incorporation of oxygen as an impurity inhibits this property. XPS measurements revealed that Mn impurities in ferromagnetic GaN:Mn samples mainly exhibit a valence state of 2þ. Cathodoluminescence (CL) spectra from Mn-doped GaN samples displayed emissions centered at about 1.97 eV, attributed to transitions between the 4 T 1-6A 1 states of the Mn 2þ d orbitals, and emissions centered at 2.45 and 2.9 eV, associated with the presence of V Ga. CL measurements also revealed a blue shift of the GaN band-edge emission generated by the expansion of the wurtzite lattice due to Mn incorporation, which was confirmed by XRD measurements. These latter measurements also revealed an amorphization of GaN:Mn due to the incorporation of oxygen as impurities. The GaN:Mn samples were synthesized by thermal evaporation of GaN and MnCO 3 powders onto Ni 0.8 Cr 0.2 /Si(100) in a horizontal furnace operated at low vacuum. The residual air inside the system was used as a source of oxygen during the synthesis of Mn and O co-doped GaN nanostructures. Mn and O impurities were incorporated into the nanostructures at different concentrations by varying the growth temperature. Energy Dispersive Spectroscopy, XRD, and XPS measurements confirmed that the obtained samples predominantly consisted of GaN.

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