Magnetic skyrmions are attracting a growing interest from both a fundamental and a technological point of view. A promising application concerns the racetrack memory, where skyrmions (moved by spin-transfer torque (STT) or spin-Hall effect (SHE)) can be used to carry the information bit, replacing domain walls [1,2,3]. Skyrmions are nucleated in out-of-plane materials, where the Dzyaloshinskii–Moriya interaction (DMI) arises: Bloch skyrmions are stabilized in the case of bulk DMI, whereas Néel skyrmions are obtained in the case interfacial DMI. Here, we show that a skyrmion racetrack memory can be obtained in four scenarios, by combining the skyrmion type and the motion source [4]. In particular, the Néel skyrmion motion driven by the SHE exhibits a large velocity-current tunability, as well as a good robustness towards surface roughness and thermal fluctuations at room temperature. Moreover, we micromagnetically prove that motion of the Néel skyrmion is mainly along the direction perpendicular to the electrical current flow (y-axis if the current is along the x-axis). This outcome is confirmed by analytical results obtained from an analytical formulation based on the Thiele’s equation: Both velocity components are proportional to jHM. However, being vx also proportional to the αG<<1, it follows that vx << vy. D References [1] A. Fert et al. Nat. Nanotech. 8, 152 (2013). [2] J. Iwasaki et al. Nat. Nanotech. 8, 742 (2013). [3] J. Sampaio et al. Nat. Nanotech. 8, 839 (2013). [4] R. Tomasello et al. Sci. Rep. 4, 6784 (2014).
Skyrmion Racetrack Memory Driven By SHE - Presentazione orale - Conferenza internazionale
ZIVIERI, Roberto;
2015
Abstract
Magnetic skyrmions are attracting a growing interest from both a fundamental and a technological point of view. A promising application concerns the racetrack memory, where skyrmions (moved by spin-transfer torque (STT) or spin-Hall effect (SHE)) can be used to carry the information bit, replacing domain walls [1,2,3]. Skyrmions are nucleated in out-of-plane materials, where the Dzyaloshinskii–Moriya interaction (DMI) arises: Bloch skyrmions are stabilized in the case of bulk DMI, whereas Néel skyrmions are obtained in the case interfacial DMI. Here, we show that a skyrmion racetrack memory can be obtained in four scenarios, by combining the skyrmion type and the motion source [4]. In particular, the Néel skyrmion motion driven by the SHE exhibits a large velocity-current tunability, as well as a good robustness towards surface roughness and thermal fluctuations at room temperature. Moreover, we micromagnetically prove that motion of the Néel skyrmion is mainly along the direction perpendicular to the electrical current flow (y-axis if the current is along the x-axis). This outcome is confirmed by analytical results obtained from an analytical formulation based on the Thiele’s equation: Both velocity components are proportional to jHM. However, being vx also proportional to the αG<<1, it follows that vx << vy. D References [1] A. Fert et al. Nat. Nanotech. 8, 152 (2013). [2] J. Iwasaki et al. Nat. Nanotech. 8, 742 (2013). [3] J. Sampaio et al. Nat. Nanotech. 8, 839 (2013). [4] R. Tomasello et al. Sci. Rep. 4, 6784 (2014).I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
