Studies of Ni and Co Doped Amorphous AlN for Magneto-optical Applications

Jadwisienczak, Wojciech M.; Tanaka, Hiroki; Kordesch, M.E.; Khan, Aurangzeb; Kaya, Savaş; Vuppuluri, Venkat

doi:10.1557/proc-1202-i05-06

Cited by 3 publications

(7 citation statements)

References 14 publications

(17 reference statements)

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“…Magnetic characterization was carried out using home build MOKE spectrograph working in polar and longitudinal configurations at room temperature as described in Ref. 6. The data collection process was computerized and multiple scans were performed to improve Kerr rotation signal to noise ratio.…”

Section: Methodsmentioning

confidence: 99%

“…The magnetic coercive force increases with annealing temperature reaching 0.6 kOe after annealing at 450°C as indicated by the width of the MOKE hysteresis loops. No longitudinal Kerr signal was observed indicating that the magnetization easy axis in a-AlN:Ni film is out of plane [6].It is known that the polar Kerr rotation, in principle, is proportional to the material magnetization; moreover it strongly depends on the morphology. Samples with small and medium Ni at.% annealed at the same conditions as samples with the largest Ni concentration show weak but monotonic increase of the MOKE signal.…”

mentioning

confidence: 98%

“…Combining the MOKE and SAXS/HRTEM one should be able to study in greater detail the evolution of the magnetic properties and their origin in magnetic materials subjected to morphological changes. Recently we have reported on the MOKE effect in a-AlN doped with nickel and cobalt [6]. In this contribution we study the effect of structural changes in the magneto-optical properties of the thermally annealed a-AlN:Ni matrix.…”

mentioning

confidence: 99%

“…The scattering patterns of the samples were first recorded by a two-dimensional (2D) detector, and then the collected 2D patterns were converted into a 1D pattern after applying corrections due to x-ray beam profile, x-ray polarization, and sample absorption, respectively. The nominal concentrations of Ni in a-AlN films sputtered using targets with different Al/Ni ratios determined by EDX ranged from a small (less than 10 at.%), to medium (~20 at.%) and large (more than 30 at.%), respectively [6]. The specimens for TEM study were grown on a glass slide using procedure described in Ref.…”

mentioning

confidence: 99%

“…The specimens for TEM study were grown on a glass slide using procedure described in Ref. [6]. Magnetic characterization was carried out using home build MOKE spectrograph working in polar and longitudinal configurations at room temperature as described in Ref.…”

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confidence: 99%

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Morphology and Magneto-optical Properties of Amorphous AlN Films Doped with Nickel

et al. 2011

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Structural and magneto-optical properties of Ni-doped amorphous AlN layers (a-AlN) deposited by radio frequency (rf) sputtering on Silicon (001) substrates were investigated. The as-grown material exhibits weak ferromagnetic behavior as evidenced by the magneto-optic Kerr effect (MOKE) measurement with Kerr rotation less than 100 µrad at room temperature regardless of the Ni fraction. The samples with a Ni concentration below 10 at.% show a weak but monotonically increasing MOKE signal with post-growth annealing temperature. A hundred-fold increase in the Kerr rotation value was observed for samples with Ni content exceeding 20 at.% after thermal annealing at 450°C in nitrogen; and the Kerr rotation value abruptly decreases above that temperature. The morphology of as-grown and annealed a-AlN:Ni films were characterized by small angle x-ray scattering and transmission electron microscopy. It was found that the as-deposited film contains nano-particles of different sizes with average diameters less than 30 nm. The size distribution of nano-particles in the thermally annealed a-AlN:Ni was studied as a function of annealing time and temperature. The results correlate well with those obtained from the MOKE measurements. INTRODUCTIONMagnetically ordered amorphous materials and magnets exhibit a wide range of technologically important materials that rely on magnetic ordering and the dynamic interactions between spin excitations and electronic transport phenomena [1,2]. Amorphous III-nitride semiconductors doped with Transition Metals (TM) and rare earth ions are suitable for prospective applications in spintronics because of a strong magnetic moment associated with the metallic impurities [3,4] and the possibility of easy modification of the magnetic domain environment. The unique feature of a-AlN:TM, in general, is that a long-range magnetic ordering is possible, while the long-range order does not exist in the distribution of constituent atoms. This implies that magnetic and nonmagnetic atoms in an a-AlN:TM lose completely the periodicity of lattice in its crystalline counterpart and form a non-crystalline solid. The high doping of magnetic transition metals is extremely difficult with the commonly used doping technique such as thermal diffusion because the solubility of the magnetic impurities is too low, especially in III-V materials [5]. Furthermore, doping with TM at high concentrations is prone to morphological inhomogeneity like nano-size precipitates and atom clustering. Experimental techniques like small angle x-ray scattering (SAXS) and high resolution transmission electron microscopy (HRTEM) allow for detailed investigations of nano-size particles embedded in a solid-state solution. The magneto-optical Kerr effect spectroscopy gives a unique opportunity to study locally magnetism in contrast to the other typically used volumetric magnetometry techniques. Combining the MOKE and SAXS/HRTEM one should be able to study in greater detail the evolution of the magnetic properties and their origin in magnetic mater...

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Section: Methodsmentioning

confidence: 99%

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confidence: 98%

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confidence: 99%

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confidence: 99%

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confidence: 99%

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Morphology and Magneto-optical Properties of Amorphous AlN Films Doped with Nickel

et al. 2011

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Cluster and Thickness Dependence of Ferromagnetism in Nickel In Situ-Doped Amorphous AlN Thin Films

Tanaka

Jadwisienczak

Kaya

et al. 2013

Journal of Elec Materi

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Structure and magnetic properties of Ni-doped AlN films

Pan

Jian

Ablat

et al. 2012

Journal of Applied Physics

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We report the crystal structure and magnetic properties of Al1−xNixN films with 0 ≤ x ≤ 0.032 deposited on Si (100) substrates by radio frequency reactive sputtering. X-ray diffractometry, x-ray photoemission spectroscopy, and x-ray absorption fine structure analysis clearly showed that Ni atoms were successfully incorporated into AlN, while the crystal structure of the films was maintained. All the doped samples exhibited ferromagnetism both at 5 K and 300 K. The saturation magnetizations (Ms) and coercive fields (Hc) tended to decrease as Ni concentration increased from 0.019 to 0.032, the maximum Ms obtained at 5 K and 300 K were about 0.025 and 0.014 emu/g, respectively, and the corresponding Hc were 208 and 60 Oe. Temperature dependence of remanent magnetization showed that the ferromagnetic transition temperature was beyond 300 K.

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Studies of Ni and Co Doped Amorphous AlN for Magneto-optical Applications

Cited by 3 publications

References 14 publications

Morphology and Magneto-optical Properties of Amorphous AlN Films Doped with Nickel

Morphology and Magneto-optical Properties of Amorphous AlN Films Doped with Nickel

Cluster and Thickness Dependence of Ferromagnetism in Nickel In Situ-Doped Amorphous AlN Thin Films

Structure and magnetic properties of Ni-doped AlN films

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