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Application of plasma focus device for deposition of nanostructured magnetic thin films and ion-irradiation induced nanostructuring of PLAD grown magnetic thin films
Citation
Rawat, R. S., Zhang, T., Lin, J. J., Pan, Z. Y., & Lee, P. (2008). Application of plasma focus device for deposition of nanostructured magnetic thin films and ion-irradiation induced nanostructuring of PLAD grown magnetic thin films. In S. H. Saw, S. Lee, C. S. Wong, R. S. Rawat, & S. L. Yap (Eds.), Proceedings of the International Workshop on Plasma Computations & Applications (pp. 23-32). University of Malaya.
Abstract
The dense plasma focus (DPF) device is a coaxial plasma gun that uses a large electric current to heat and compress a gas to high temperatures (1-2 keV), densities (1025-26 m-3) and pressures (thousands of atmospheres). Under such extreme conditions, the gas radiates copious ultraviolet, X-rays and particle beams such as relativistic electrons and ion beams. At Plasma Radiation Sources Laboratory (PRSL), NIE, Singapore, our group has six plasma focus devices and our research efforts encompass a very wide range of topics covering various fundamental aspects of plasmas to the application of this device to lithography, soft and hard x-ray imaging, material modification and thin film deposition. This review paper reports the use of single shot and “repetitive” PF device for processing and deposition of thin films using plasma focus devices. To synthesize the magnetic thin films, the conventional hollow copper anode was substituted with an anode fitted with suitable material tip (FeCo or CoPt). Si wafer and copper mesh were placed axial down the anode axis at a suitable distance of about 25 cm above the anode top to improve the uniformity of deposited samples over bigger substrate size. The plasma focus device is operated at 1 Hz repetition rate at various combinations of charging voltage and filling pressure of hydrogen gas for different number of focus deposition shots. For the processing of thin films, the magnetic thin films of FePt were initially deposited using pulsed laser deposition and later exposed to energetic ions from hydrogen operated plasma focus device. The morphology, structure and magnetic properties of the synthesized and processed thin films are investigated using TEM, SEM, XRD and VSM, respectively. The paper will also discuss the fundamental of thin film deposition and irradiation mechanisms in plasma focus devices.
Date Issued
July 2008
Description
This paper was presented at the International Workshop On Plasma Computations & Applications (IWPCA 2008), held in Kuala Lumpur, Malaysia from 14 - 15 Jul 2008