No abstract

We model "soft" error rates for writing (WSER) and for reading (RSER) for perpendicular spintorque memory devices by solving the Fokker-Planck equation for the probability distribution of the angle that the free layer magnetization makes with the normal to the plane of the film. We obtain: (1) an exact, closed form, analytical expression for the zero-temperature switching time as a function of initial angle; (2) an approximate analytical expression for the exponential decay of the WSER as a function of the time the current is applied; (3) comparison of the approximate analytical expression for the WSER to numerical solutions of the Fokker-Planck equation; (4) an approximate analytical expression for the linear increase in RSER with current applied for reading; (5) comparison of the approximate analytical formula for the RSER to the numerical solution of the Fokker-Planck equation; and (6) confirmation of the accuracy of the Fokker-Planck solutions by comparison with results of direct simulation using the single-macrospin Landau-Lifshitz-Gilbert (LLG) equations with a random fluctuating field in the short-time regime for which the latter is practical.

No abstract

Abstract. Measurements of the exchange stiffness D and the exchange constant A of Yttrium Iron Garnet (YIG) films are presented. The YIG films with thicknesses from 0.9 µm to 2.6 µm were investigated with a microwave setup in a wide frequency range from 5 to 40 GHz. The measurements were performed when the external static magnetic field was applied in-plane and out-of-plane. The method of Schreiber and Frait [1], based on the analysis of the perpendicular standing spin wave (PSSW) mode frequency dependence on the applied out-of-plane magnetic field, was used to obtain the exchange stiffness D. This method was modified to avoid the influence of internal magnetic fields during the determination of the exchange stiffness. Furthermore, the method was adapted for in-plane measurements as well. The results obtained using all methods are compared and values of D between (5.18 ± 0.01) · 10 −17 T·m 2 and (5.34±0.02)·10 −17 T·m 2 were obtained for different thicknesses. From this the exchange constant was calculated to be A = (3.65 ± 0.38) pJ/m. arXiv:1408.5772v1 [cond-mat.mtrl-sci]

Using a combination of first-principles calculations and an extended Hückel tight binding model this letter reports on the origin of the low Gilbert damping in half metals. This approach enables the prediction of the lower limit for the magnetization relaxation in a wide variety of material systems relevant for future spintronic applications. For the two model systems Co2MnGe and Co2MnSi minimal damping parameters of 1.9×10−4 and 0.6×10−4 are predicted.