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High saturation magnetization soft m...

Sun, Nian-xiang.

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High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications./
作者:	Sun, Nian-xiang.
面頁冊數:	179 p.
附註:	Adviser: Shan X. Wang.
Contained By:	Dissertation Abstracts International63-01B.
標題:	Engineering, Electronics and Electrical. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3038160
ISBN:	0493519947

High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications.
Sun, Nian-xiang.

High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications. - 179 p.

Adviser: Shan X. Wang.

Thesis (Ph.D.)--Stanford University, 2002.

In this work, Fe-Co-N alloy films with the thickness of 100 nm with a Permalloy nano-underlayer (<5 nm) have been synthesized and characterized. The Fe-Co-N films have a high saturation magnetization of 2.4 T (24 kG), a low coercivity of less than 80 A/m (1 Oe), a resistivity of 50 μΩ·cm, and an initial permeability of 1000 with a 3dB bandwidth of 1.5 GHz. The combination of high saturation magnetization, low coercivity, and high bandwidth makes the Fe-Co-N thin film a very promising candidate material for magnetic recording heads. An exchange induced ripple reduction mechanism is proposed to explain the observed magnetic softness in the Fe-Co-N films with a Permalloy nano-underlayer. Pulsed inductive magnetometer studies show that the Fe-Co-N films exhibit a ferromagnetic resonance frequency of 2 GHz. The Fe-Co-N films with larger dispersion angles generally show higher damping constants. The susceptibility spectrum of a magnetic thin film is obtained from the Landau-Lifshitz-Gilbert (L-L-G) Equation and is analyzed to obtain the damping criteria for magnetic thin films. The damping criteria for a magnetic thin film with the relative dc susceptibility χ<italic>0</italic> = χ(ω = 0) = <italic>Ms</italic>/(<italic>Hk</italic>+<italic> Happl</italic>) are α > 2χ<super>−1/2</super>, over damped; α = 2χ<super>−1/2</super>, critically damped; and 0 < α < 2χ<super>−1/2</super>, under damped. Since the actual damping constants for the magnetic thin films are far less than 2χ<super>−1/2</super>, the magnetic thin films are generally observed to be under-damped. A general method of solving the L-L-G equation and the Landau-Lifshitz (L-L) equation in the frequency domain is proposed, and is used to solve the L-L-G equation and the L-L equation for a magnetic sphere and a magnetic thin film. The different harmonic terms of the magnetization are also predicted for a magnetic sphere and a thin film from the L-L-G equation and the L-L equation.

ISBN: 0493519947Subjects--Topical Terms:

626636
Engineering, Electronics and Electrical.

High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications.
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245 1 0 $a High saturation magnetization soft magnetic iron-cobalt-nickel films for GHz applications.
300 $a 179 p.
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500 $a Source: Dissertation Abstracts International, Volume: 63-01, Section: B, page: 0473.
502 $a Thesis (Ph.D.)--Stanford University, 2002.
520 $a In this work, Fe-Co-N alloy films with the thickness of 100 nm with a Permalloy nano-underlayer (<5 nm) have been synthesized and characterized. The Fe-Co-N films have a high saturation magnetization of 2.4 T (24 kG), a low coercivity of less than 80 A/m (1 Oe), a resistivity of 50 μΩ·cm, and an initial permeability of 1000 with a 3dB bandwidth of 1.5 GHz. The combination of high saturation magnetization, low coercivity, and high bandwidth makes the Fe-Co-N thin film a very promising candidate material for magnetic recording heads. An exchange induced ripple reduction mechanism is proposed to explain the observed magnetic softness in the Fe-Co-N films with a Permalloy nano-underlayer. Pulsed inductive magnetometer studies show that the Fe-Co-N films exhibit a ferromagnetic resonance frequency of 2 GHz. The Fe-Co-N films with larger dispersion angles generally show higher damping constants. The susceptibility spectrum of a magnetic thin film is obtained from the Landau-Lifshitz-Gilbert (L-L-G) Equation and is analyzed to obtain the damping criteria for magnetic thin films. The damping criteria for a magnetic thin film with the relative dc susceptibility χ<italic>0</italic> = χ(ω = 0) = <italic>Ms</italic>/(<italic>Hk</italic>+<italic> Happl</italic>) are α > 2χ<super>−1/2</super>, over damped; α = 2χ<super>−1/2</super>, critically damped; and 0 < α < 2χ<super>−1/2</super>, under damped. Since the actual damping constants for the magnetic thin films are far less than 2χ<super>−1/2</super>, the magnetic thin films are generally observed to be under-damped. A general method of solving the L-L-G equation and the Landau-Lifshitz (L-L) equation in the frequency domain is proposed, and is used to solve the L-L-G equation and the L-L equation for a magnetic sphere and a magnetic thin film. The different harmonic terms of the magnetization are also predicted for a magnetic sphere and a thin film from the L-L-G equation and the L-L equation.
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