Thermal Stability of Ni-C Multilayer Mirror for X-Rays

Nakajima, Kunio; Aoki, Sadao; Fujiwara, S.

doi:10.1143/jjap.31.2864

Cited by 11 publications

(1 citation statement)

References 22 publications

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“…While the microstructure is often deliberately modified to tailor material properties [for example, inducing spin-reorientation transition (Weller et al, 2000), magneticnon-magnetic transition (Dev et al, 2006) and, vice versa, introducing impurities (Bera et al, 2007b), extending the energy range for reflectivity], it may become naturally modified/damaged during actual applications [e.g. heating (Nakajima et al, 1992;Kapta et al, 2004), X-ray beam impingement (Bera et al, 2003;Takacs et al, 1985)]. It is important to understand these structural changes in order to assess the stability of device functionality.…”

Section: Introductionmentioning

confidence: 99%

Ascertaining the nanocluster formation within an ion-irradiated Pt/Ni/C multi-trilayer with X-ray absorption spectroscopy

Ramanan

Roy

Lahiri

et al. 2012

J Synchrotron Radiat

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In this work nanoclusters formed in a Pt/Ni/C multi-trilayer by the ion-irradiated method of synthesis are characterized. In particular, an attempt to understand the role of interfaces in the synthesis is made. With this objective, ion-irradiation-induced structural changes in a Pt/Ni/C multi-trilayer using X-ray absorption spectroscopy (at the Ni K-edge) in conjunction with the X-ray standing-wave technique are investigated. The XANES analysis identifies chemical binding at pristine Ni/C and Ni/Pt interfaces, in contrast with physical adsorption at the Pt/C interface. The chemical nature of the interfaces determines their relative stability with respect to irradiation and controls the extent of metallic diffusion. The most interesting structural change, upon irradiation, is the disruption of the Pt/C interface and subsequent migration of Pt atoms towards pre-diffused Ni atoms within the C layer, leading to the formation of Ni-centered Ni-Pt bimetallic nanoclusters (with Ni:Pt = 60:40). These clusters are highly disordered beyond their nearest neighbor and find wide-scale applications as, for example, magnetic devices etc. The implications of these findings on the design goals are discussed.

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Section: Introductionmentioning

confidence: 99%

Ascertaining the nanocluster formation within an ion-irradiated Pt/Ni/C multi-trilayer with X-ray absorption spectroscopy

Ramanan

Roy

Lahiri

et al. 2012

J Synchrotron Radiat

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Thermal Ageing of Ni/C Multilayers Prepared by Pulsed Laser Deposition

Krawietz

Wehner

Kallis

et al. 1994

Phys. Stat. Sol. (a)

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Ni/C multilayers are prepared by pulsed laser deposition with different laser wavelengths. Specimens providing different interface constitutions are investigated in the initial state and after an annealing time of 20 min at temperatures between 50 and 400 °C. X‐ray reflectometry and X‐ray diffraction at grazing incidence of the radiation are applied for the characterization of the samples. An increase of the double layer thickness with increasing temperature is observed for all multilayer samples. Generally this process starts at temperatures between 100 and 250 °C, but the sample with graded interfaces remain stable up to higher temperatures than those with abrupt interfaces. After heating at 400 °C the initially almost amorphous nickel layers crystallize in a thermodynamically stable f.c.c. lattice structure. For the sample with abrupt interfaces intermixing of nickel and carbon during deposition leads to the formation of crystalline nickel carbide between 200 and 300 °C.

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