MRAM

Controllable Remanent States on Microstructured

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Fig.1.SEM micrograph shows the complete magnetic tunnel junction ring devices with an outer diameter of 2/1 and inner diameter of 1/0.5 . m


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Fig.2.MR loops for sample A. (a) Major loop. (b) Minor loop (curve 1) and subloops (curves 2 and 3) measured from negative free layer saturation field.
The bottom and top layer of insets represent the magnetization configuration of pinned and free layer, respectively. (c) Minor loop (curve 1) and subloops(curves 4 and 5) measured from positive free layer saturation field.


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Fig.3.MR loops for sample B. (a) Minor loop (curve 1) and subloop (curve2) measured from negative free layer saturation field. (b) Minor loop (curve 1) and subloop (curve 3) measured from positive free layer saturation field.

Fabrication and Characterization of Microstructured

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Fig.1.Cross-sectional scheme of fabrication processes of a ring-shaped MTJ device.


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Fig.2.MR curve of the ring-shaped MTJ device shows 16% MR ratio with RA . 17 k 2.m  .


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Fig.3.MR minor loop reveals a clear fourtransition reversal process. The upper inset indicates

the directions of external field and biasing.The lower insets illiustrate the magnetization configurations of free and  pinned  layers corresponding to the steps as the field in the sweep-up process. Hci represents the field for each transition on the free layer. Note that the magnetization in the pinned layer is supposed to be in the uniformly horizontal direction.


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Fig.4.MFM images of ring-shaped MTJ cell. The images were taken in situ under the magnetic field range from +184 Oe to 0 133 Oe after saturation field of 300 Oe. The arrow presents the field direction.