Sputter synthesized and pulsed laser deposited soft and hard ferrimagnetic compounds.
Item
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Title
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Sputter synthesized and pulsed laser deposited soft and hard ferrimagnetic compounds.
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Identifier
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AAI9618099
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identifier
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9618099
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Creator
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Samarasekara, Pubudu.
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Contributor
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Adviser: F. J. Cadieu
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Condensed Matter
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Abstract
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We have deposited soft and hard ferrimagnetic compounds using Nd:YAG pulsed laser deposition and rf sputtering techniques. Soft ferrimagnetic material materials are useful in microwave and millimeter wave monolithic integrated circuits such as isolators, circulators, and phase shifters, magneto-optic recording media. The hard ferrimagnetic compounds are also used in magnetic recording and microwave devices. We have deposited cubic (or soft) magnetic materials such as {dollar}\rm NiFe\sb2O\sb4{dollar} and (Li,Ti,Mn,Zn) {dollar}\rm Fe\sb5O\sb8,{dollar} and hexagonal (or hard) ferrimagnetic compounds such as {dollar}\rm SrFe\sb{12}O\sb{19}.{dollar} For the first time we have deposited non-epitaxial Sr ferrite films with strong (110) texture on {dollar}\rm Al\sb2O\sb3{dollar} polycrystalline substrates using rf sputtering at deposition temperatures as low as 500{dollar}\sp\circ{dollar}C in 100 mTorr of Ar gas. The coercivity of films drastically increases from 0.5 kOe to 3.8 kOe with annealing in oxygen of 500 Torr. We have synthesized Ni ferrite films with complete (111) texture without any content of other crystallites on C-plane sapphire substrates at 930{dollar}\sp\circ{dollar}C using pulsed laser deposition in 200 mTorr of oxygen. Also we have laser ablated (400) textured Ni ferrite films on R-plane sapphire substrates at 910{dollar}\sp\circ{dollar}C. Any other oriented Ni ferrite film depositions have not been reported before this work. In addition to these, the highly (111) textured (Li,Ti,Mn,Zn) mixed ferrite films have been fabricated on C-plane sapphire at 930{dollar}\sp\circ{dollar}C using laser ablation. The other elements have been added to Li ferrite to lower the saturation magnetization, to make them more useful in microwave applications. In all these cases, the texture of film remarkably depends on the substrate temperature.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
