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 nm/Cu 3.7 nm/CoFe 1.5 nm/NiFe 4.5 nm/Ta 20 nm. Minimum resistance (R_min), storage layer switching fields in forward and reverse sweep directions (H_f and H_r) for write, and resistance change (ΔR) for readback are reported as a function of temperature (25 to 100°C) and bit width (500 to 900 nm). R_min and ΔR temperature coefficients are reported as a function of sense current (0.1 to 1 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°C to account for bit width (BW), was approximately +1.4 mΩ/°C/Ω. The variation of ΔR with temperature, normalized to R_min at 25°C, was approximately -60 μΩ/°C/Ω. The temperature dependences of R_min and ΔR were attributed to increased scattering as thermal energy increased. H_f and H _r show weak temperature dependence, between approximately 0 and -25 mOe/°C and 0 and +25 mOe/°C, 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