Current-induced magnetization reversal in SrRuO${}_3$

We inject current pulses into uniformly magnetized patterns of thin films of the itinerant ferromagnet SrRuO${}_3$, while monitoring the effective temperature of the patterns during the current injection. We gradually increase the amplitude of the pulses until magnetization reversal occurs. We observe magnetization reversal induced by current above a temperature-dependent threshold and show that this effect is not simply due to sample heating or Oersted fields. We discuss the applicability of the current-induced spin-wave instability scenario.

Figure 1

The magnetization reversal field vs temperature in the absence of current effects (the measuring current is 30 $\mu$A). Inset: The antisymmetric transverse resistance vs temperature with reversing fields between 1 and 3 kOe. The sharp jumps are attributed to magnetization reversal.

Figure 2

(a) The longitudinal resistance measured between two neighboring voltage leads vs temperature. Inset: A scheme of the pattern. (b) The longitudinal resistance ($R_{xx}$) vs pulse duration. The pulse amplitude varies between 2.57 and 5.8 mA, and the initial temperature varies between 100 and 30 K, respectively. $R_{xx}$ is measured during the last 50 $\mu$s of the pulse. Inset: The change in the local temperature vs the current's power. The pulse duration is 1 ms. (c) The longitudinal resistance during the last 50 $\mu$s of the pulse vs the pulse amplitude for different initial temperatures. The total pulse duration is 1 ms.

Figure 3

(a) The effective temperature (left) and the normalized average magnetization, $M^{*}$ (right) vs current amplitude for $T_b=70$ K and a reversing field of $H=100$ Oe. The dashed lines are guidelines for the magnetization reversal current $I_n$ and the magnetization reversal temperature $T_n$. (b) The magnetization reversal temperature $T_n$, at $H=0$ and 2000 Oe vs the magnetization reversal current. The solid lines represent the magnetization reversal temperature in the limit of zero current.

Figure 4

Reversal events (big red dots) and nonreversal events (small gray dots) in ($I$, $H$) phase space for $T_{\mathrm{eff}}$ ($\pm$3 K) between 102 and 120 K. The dashed lines represent $H_n$ in the limit of zero current at the upper bound of the temperature regime, and the solid lines represent the threshold currents $I_t$.

Figure 5

The switching current at zero field $I_n^0$ (red dots) and the threshold current $I_t$ (blue squares) as a function of temperature.