High-Density Physical Random Number Generator Using Spin Signals in Multidomain Ferromagnetic Layer

Figure 2

Schematic diagram showing scheme for generating random bit sequence using the pMTJ. The DC currents are applied to the pMTJs, flowing from the pinned to the free layer. A constant, positive magnetic field (100 Oe) is simultaneously applied by a gauss-meter to correct the shift field. Electrical output signals for spin magnetization arrangements are extracted at 20 kbps using a Keithley 2636 A sourcemeter. The output voltage signals are normalized to the form . The normalized signals are digitized using fixed-point arithmetic (16-bit). The least signification bits (LSBs) of the digitalized signal are used for binary signals. Finally, the binary signals obtained from the pMTJs are combined using an exclusive OR (XOR) method to generate a bit sequence. The single cell data method refers to data processing in only one pMTJ before the XOR operation.