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PRESENTED BY. Zamara Nasir PPHF13E019. We are going to discuss…. Neel Orange-Peel coupling in Magnetic Tunneling junction devices. Contents:. Measurement of magnitude of Orange-Peel coupling Results from 1- Magnetometry

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  1. PRESENTED BY Zamara Nasir PPHF13E019

  2. We are going to discuss… Neel Orange-Peel coupling in Magnetic Tunneling junction devices

  3. Contents: • Measurement of magnitude of Orange-Peel coupling • Results from 1- Magnetometry 2- Transmission electron microscopy

  4. Tunnel Junctions: • It is a barrier consist of any insulating layer or may be a electric potential between two conducting layers. • Electrons pass through the barrier Magnetic Tunnel junction: • electrons tunnel through a thin insulating barrier from one magnetic material to another.

  5. Magnetic tunnel junction

  6. Magnetic Inter layer Coupling Two ferromagnetic layers are coupled • control or eliminate the stray magnetic field affecting the free ferromagnetic layer Two types of magnetic fields produced in layer • Magneto static: (due to uncompensated poles near the edges ,layer~3-5nm) • Neel Orange-Peel: ( due to roughness of interface)

  7. Neel Orange-Peel coupling: • 12 samples were made and studied of same layer composition but different thickness. • one sample is Si(100)substrate/Ta/Al/NiFe/FeMn/Co(P2)/Ru/ Co(P1)(pinned)/Al2O3(barrier)/NiFe(free)/Al/Ta

  8. Hysteresis loop • Resistance versus field curve define the hysteresis loop of free layer • Experiment was done on chips(rectangular junctions) of micron order by applying 2D field • Extract values of switching field and bias field • For bulk material VSM (vibrating sample magnetometry) is used

  9. for such sizes of samples we cannot ignore magneto static coupling so we have to separate couplings by varying the thickness of junction. • Interface roughness parameters were obtained from Neel field strength • Neel assumed a sinusoidal roughness profile and give a field expression

  10. Schematic of coupling mechanism

  11. here h= amplitude of rough profile λ= wavelength of rough profile tf= thickness of free layer ts= thickness of barrier Ms = magnetization of free layer

  12. TEM: (Transmission electron microscope ) From micrograph • Image was converted into data points related to vertical position of barrier interface as a function of horizontal distance along sample. • position of all maxima and minima were recorded • wavelength and amplitude were obtained from adjacent maxima and minima according to that points • data was plotted into a histogram

  13. According to distribution

  14. Comparison:

  15. References • Neel “orange-peel” coupling in magnetic tunneling junction devices by B. D. Schrag, A. Anguelouch, S. Ingvarsson, Gang Xiao, Yu Lu et al. Published by American Institute of Physics. • J. S. Moodera, L. R. Kinder, T. M. Wong, and R. Meservey, Phys. Rev.Lett. 74, 3273 (1995); J. Appl. Phys. 79, 4724 (1996)

  16. QUESTIONS?????.....

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