2ydim3

WP5: “Study of magnetization processes” Starting date: month nr. 3, duration 33 monthstask leader: V. Alexandrakis: 

WP5: “Study of magnetization processes” Starting date: month nr. 3, duration 33 months task leader: V. Alexandrakis { Objectives Determination of the best candidate for high density magnetic recording. Optimisation of the magnetic properties (magnetooptical effect and dynamical behavior). Magnetisation reversal, Bloch wall pinning, magnetic coupling, demagnetising field effects, high frequencies dynamics, switching time (SQUID magnetometer, AC susceptometer, MOKE, MFM).

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Our multilayered structure Substrate Si (glass) (001) 1 2 15 ~ . 7 nm ~ 0.2nm { Total thickness  100-200 Å Optimised thickness For max Hc { (Com/Pdn)}z (Si, glass) ~ 12 nm

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{ HIDEMAR - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass)

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{ HIDEMAR - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass)

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{ HIDEMAR - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass) N°: A1 Aproximate thickness of layers: 120(Pd) + (2,1 Co/ 7,7 Pd) *15 Gasflow: 60 sccm Ar Pressure: 37 µbar substrate: glass Hc = 5520 Oe Sample caracteristics : Time dependence for sample A1

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{ DYNAMICS - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass) N°: A5

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{ DYNAMICS - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass) Gasflow: 20 sccm Ar Pressure: 11 µbar substrate: Silicon Hc = 680 Oe Aproximate thickness of layers: B8 120(Pd) + (2,8 Co/ 7,7 Pd) *15

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{ DYNAMICS - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass) Thermally activation dynamics for the sample B4: the slope gives a value of 600 nm3 for the activation volume, which, taking into account total magnetic sample thickness of 0.28 x 15 = 4.2 nm, leads to a characteristic size of magnetic grains of 10-15 nm.

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{ DYNAMICS - RESULTS Our multilayered structure { (Com/Pdn)}z (Si, glass) DYNAMICS USING KERR EFFECT

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{ Task.1 MOSSBAUER SPECTROSCOPY FePt/Ag/Au

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{ Task.2 High frequencies dynamics, switching time We have purchased a Vector Network Analyser Anritsu 37269B ( 45 MHz- 40 GHz) for dynamic magnetoresistance and switching mechanism measurements using the stripline technique measurements and S-parameters evaluation. Expected operation before the end of 2004.

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{ Task.2 High frequencies dynamics, switching time

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