Read Back Signals in Magnetic Recording - Research Group Fidler

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∂ ∂n 2 1 2 1 ( H () r − H () r ) =− n× ( j () r −j() r ) Appendix B . (B.14) 82
List of Figures List of Figures Figure 1.1: The original drawing of Oberlin Smith (1888) and Valdemar Poulson’s telegraphone [2].................................................................................................................7 Figure 1.2: The first computer disk drive RAMAC. The pneumatically driven actuator arm and some of the 50 disks are visible [4].....................................................................8 Figure 1.3: The development of bit sizes and storage densities over the last years [7]. ........10 Figure 2.1: a) Illustration of the damped precession of the magnetic polarization J around the effective field Heff, taken from [15]. b) Influence of the Gilbert damping constant on the field rise time in magnetic read heads. Head field strength as a function of time for different Gilbert damping constants within the head [43]. The dashed line depicts the current profile. The solid lines give the head field for α = 1, 0.5, 0.1, and 0.02. The fastest field rise time is achieved with intermediate damping (α = 0.5).......................................................................................20 Figure 2.2: The spin-split bands of a ferromagnet [18]..........................................................21 Figure 2.3: Giant magnetoresistance in Fe/Cr multilayers [18]. ............................................22 Figure 2.4: Schematic model of a spin-valve GMR head (CIP mode) with exchangepinned layer and longitudinal hard bias [19]...................................................................23 Figure 2.5: Change in resistance of a spin valve compared to AMR (NiFe) vs. magnetization orientation [19]. .......................................................................................23 Figure 2.6: The two different modes of a spin valve. The current is applied either longitudinal (CIP) or perpendicular (CPP) to the layer structure [7]. .............................24 Figure 2.7: Potential landscape inside the FM/NM/FM active part of a spin-valve, for the two spin channels in the parallel state (a,b) and in the antiparallel state (c), indicating the different origins of scattering [20]............................................................25 Figure 2.8: A comparison of longitudinal recording and perpendicular recording [7]. .........27 Figure 3.1: A schematic 2-dimensional model of a read head for longitudinal recording..........................................................................................................................30 Figure 3.2: The magnetic potential at the ABS under Karlquist approximation....................31 Figure 3.3: The x- and the z-component of the normalized head field of a read head with 60 nm gap, and sensing layer thickness 5 nm, 10 nm below the ABS....................33 Figure 3.4: The effective signal field as function of the relative position of the read head in respect to a perfect transition (Js = 0.5 T)...........................................................35 Figure 3.5: These two figures show the x-component of the magnetization (Js = 0.5 T) of the data layer after a write process with head velocity 10 m/s (left) and 20 m/s 83
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DIPLOMARBEIT Read Back Signals in M
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Abstract This thesis concentrates o
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Contents 3.2.4 Signal of Written Bi
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Introduction 1 IntroductionEquation
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Introduction In 1955, before the RA
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2 BasicsEquation Section (Next) 2.1
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Basics curl H = 0 . (2.15) So H is
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Basics This is justified, because t
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Basics Here J ij represents the exc
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s Basics ∂J α ∂J =−γ J× He
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Basics for spin down electrons. An
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Basics Figure 2.4: Schematic model
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Basics channels in the parallel and
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Basics Nowadays there are again eff
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Analytical Calculations 3 Analytica
Page 31 and 32: Analytical Calculations developing
Page 33 and 34: Analytical Calculations t C 8 π =
Page 35 and 36: µ 0 Hsig [T] 0.030 0.025 0.020 0.0
Page 37 and 38: Analytical Calculations n n ⎛HH,
Page 39 and 40: z Analytical Calculations Figure 3.
Page 41 and 42: 4 Numerical MethodsEquation Numeric
Page 43 and 44: Numerical Methods ϕ ( x ) =δ . (4
Page 45 and 46: Numerical Methods current flowing o
Page 47 and 48: Numerical Methods ∫ ∫ ∫ si =
Page 49 and 50: Numerical Methods Figure 4.2: The l
Page 51 and 52: Numerical Methods j =−σgrad Φ.
Page 53 and 54: Numerical Methods within the volume
Page 55 and 56: Numerical Methods Integration of Am
Page 57 and 58: 4.5 Time integration Numerical Meth
Page 59 and 60: 5 Read Head DesignEquation 5.1 Bias
Page 61 and 62: Read Head Design The exchange bias
Page 63 and 64: Read Head Design free layer (see Fi
Page 65 and 66: FEM Simulations 6 FEM SimulationsEq
Page 67 and 68: FEM Simulations Magnetic Material J
Page 69 and 70: 6.2 Results FEM Simulations In the
Page 71 and 72: Output [V] 0.108 0.107 0.106 0.105
Page 73 and 74: FEM Simulations has a greater influ
Page 75 and 76: Output Voltage [V] 0.1074 0.1072 0.
Page 77 and 78: 7 OutlookEquation Section (Next) Ou
Page 79 and 80: Appendix A In case we have the func
Page 81: Appendix B Moreover the second inte
Page 85 and 86: List of Figures Figure 6.1: The mag
Page 87 and 88: Bibliography [11] H. Katayama, M. H
Page 89 and 90: Bibliography [38] W. F. Brown Jr.,
Page 91: Lebenslauf Otmar Ertl Reinprechtsdo
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Read Back Signals in Magnetic Recording - Research Group Fidler

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