Research Project Highlight

 

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Project-I: Controlling of magnetic states in Ferromagnetic Nanorings (Application for Data Storage and MRAM devices)

Ferromagnetic nanorings have potential applications to high density data storage and MRAM (Magneto resistive random access memory) devices due to their potential to store information with magnetic properties instead of electric. Ferromagnetic rings have been proposed as a practical type of non-volatile data storage devices. Three novel states exhibit by nanorings are single domain, onion, and vortex. In addition to these twisted state has been observed. Rotational or translational motion of the DWs observed during the switching from onion to reverse onion or onion to vortex state.

We came upon a method of manipulating the magnetic states of individual ferromagnetic nanorings using an azimuthal Oersted field directed along the ring arm circumference. The direction and magnitude of the field are determined by passing a current through a solid metal atomic force microscope probe into a metal under layer. Nanorings are fabricated by electron-beam lithography techniques with electron beam evaporation of magnetic materials followed by lift-up method.

(a)Schematic of the experiment setup. (b) A current-voltage plot generated directly from the experimental setup in (a).

By applying circular field we can directly switch from Onion to Vortex-CW  and Vortex-CCW states. We can also switch between two vortex state with applied CW and CCW circular field.

 

Onion-Vortex-Onion switching process in symmetric CoNR

Onion-Vortex-Onion switching process in asymmetric CoNR

 

Novel magnetic states observed in ferromagnetic nanorings

 

 

 

Project-II: Study of Domain Wall motion in ferromagnetic nanowires by injecting current pulses

AFM Height image of CoNWs

Magnetic Force Microscopy (MFM) images of CoNWs. A Bright and Dark spot shows the Domain Walls at 10mT in-plane magnetic field vertically downward direction.

The ultimate goal of this research work is to study the DW motion along the nanowires by injecting current pulses for data storage and MRAM applications.