Pseudo-spin-valve device performance for giant magnetoresistive random access memory applications

Write and read performance were characterized in current-in-plane pseudo-spin-valve (PSV) devices. The PSV stack evaluated in this work was Ta 5 nm/NiFe 6.5 nm/CoFe 1.5 mn/Cu 3.7 nm/CoFe 1.5 nm/NiFe 4.5 nm/Ta 20 nm. Minimum resistance (Rain), storage layer switching fields in forward and reverse sweep directions (H-f and H-r) for write, and resistance change (DeltaR) for readback are reported as a function of temperature (25 to 100 degreesC) and bit width (500 to 900 nm). R-min and DeltaR temperature coefficients are reported as a function of sense current (0.1 to I mA), I-s. H-f and H-r temperature coefficients are reported as a function of I-s and applied hard-axis field (0 to 30 Oe), H-d. The variation of R-min with temperature, normalized to R-min at 25 IC to account for bit width (BW), was approximately +1.4 m Ohm/degreesC/Ohm. The variation of DeltaR with temperature, normalized to R-min at 25 degreesC, was approximately -60 mu Ohm/degreesC/Ohm. The temperature dependences of R-min and DeltaR were attributed to increased scattering as thermal energy increased. H-f and H-r show weak temperature dependence, between approximately 0 and -25 mOe/degreesC and 0 and +25 mOe/degreesC, respectively. The weak temperature dependence of H-f and H-r was ascribed to the weak temperature dependence of magnetization, anisotropy, and exchange over the measured range of temperatures.