New magnetically uniaxial phases in the samarium, iron binary system.
Item
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Title
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New magnetically uniaxial phases in the samarium, iron binary system.
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Identifier
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AAI9521308
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identifier
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9521308
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Creator
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Rani, Raj.
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Contributor
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Adviser: F. J. Cadieu
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Date
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1995
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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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For the first time, films magnets of binary {dollar}\rm Sm\sb5Fe\sb{17}{dollar}, and SmFe{dollar}\sb{12}{dollar}, magnetically uniaxial phases have been sputter synthesized without any addition of a phase stabilizing third element. Perpendicular to the film plane, the room temperature saturation magnetization for highly (002) aligned film samples of SmFe{dollar}\sb{12}{dollar} phase were measured to be 14.3 {dollar}\pm{dollar} 0.5 kG and the estimated anisotropy field was 130 {dollar}\pm{dollar} 10 kOe. X-ray diffraction studies, hysterisis loop measurements, composition measurements, and projection of moment calculations allowed to identify the SmFe{dollar}\sb{12}{dollar} phase as ThMn{dollar}\sb{12}{dollar} type tetragonal structure with a = 8.438 {dollar}\pm{dollar} 0.006 A, and c = 4.805 {dollar}\pm{dollar} 0.006 A. Film samples of this phase were synthesized by depositing the material on preheated substrates. For {dollar}\rm Sm\sb5Fe\sb{17}{dollar} phase, the material was first deposited in amorphous form and subsequently crystallized. {dollar}\rm Sm\sb5Fe\sb{17}{dollar} film samples were synthesized with record high room temperature coercivity of 14.1 kOe for the two element Sm, Fe system. On nitriding {dollar}\rm Sm\sb2Fe\sb{17}{dollar}, profound changes in magnetic properties have occurred, room temperature inplane coercivity rose from 0.75 kOe to 23 kOe. The {dollar}\rm Sm\sb2Fe\sb{17}N\sb{lcub}x{rcub}{dollar} compound retained its parent structure with the cell volume increase of {dollar}\approx{dollar}7%. The room temperature coercivity as a function of the Sm concentration reached a maximum value of {dollar}\approx{dollar}23 kOe at a slightly richer than stoichiometric Sm composition. High anisotropy (002) textured film samples of {dollar}\rm Pr(Fe\sb{lcub}12-y-z{rcub},Co\sb{lcub}y{rcub},Mo\sb{lcub}z{rcub})N\sb{lcub}x{rcub}{dollar}, where y = 0-2.5, and z = 0.4-1.0 compounds were synthesized with so far the highest coercivity of 9.4 kOe. X-ray diffraction data showed that the ThMn{dollar}\sb{12}{dollar} type tetragonal structure was retained with a saturation increase in the cell volume over the first 15 minutes of nitriding time at 750 K. The coercivity reached a maximum for nitriding time of 25 minutes of nitriding time. For {dollar}\rm Pr\sb{lcub}1.04{rcub}Fe\sb{lcub}10.36{rcub}Co\sb{lcub}1.16{rcub}Mo\sb{lcub}0.44{rcub}N\sb{lcub}x{rcub}{dollar} sample measured at 293 K, perpendicular to the film plane saturation magnetization, coercivity, and energy product were 11.6 {dollar}\pm{dollar} 0.5 kG, 9.4 kOe, and 23.6 Million Gauss-Orested, respectively. These film magnets find their applications in storage media, microwave devices, and small film-scale permanent magnet geometries, etc.
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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.
