Figure 5
Simultaneous manipulation and monitoring of magnetic particle. (a) A photo of the magnetic spider web chip integrated with the magnetoresistive (MR) sensor at the web center and the dummy sensor fabricated in the same batch. (b) The MR signal profiles for dummy and active sensors integrated with the spider web patterns. (c) Calculated stray field distribution of single particle on sensor surface; color bar is normalized by −691.4 μT. (d) Landscape of effective stray field depending on the particle location with respect to sensing area of the sensor, −1.130 μT near center (light blue), marked as ①, −3.487 μT near edge (dark blue), marked as ②, and positive 3.069 μT, marked as ③ (red color); color bar is normalized by −3.487 μT. (e) Relative of stray field variation as a function of increasing particle coverage area (blue line: Hmax(ave), average stray field; red line: Hmax(max), descending order stray field inside sensing area; black line: Hmax(min), ascending order of stray field inside sensing area). (f) The MR signal during particle converging and diverging at the sensor surface, where the MR signal variation becomes saturated and desaturated after only a few rotating field cycles. The percentage of coverage of the sensor surface that resulted with particle accumulation based on rotating field cycles is presented in (f).
