ترغب بنشر مسار تعليمي؟ اضغط هنا

Voltage-induced precessional switching at zero-bias magnetic field in a conically magnetized free layer

70   0   0.0 ( 0 )
 نشر من قبل Rie Matsumoto
 تاريخ النشر 2018
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Voltage-induced magnetization dynamics in a conically magnetized free layer with an elliptic cylinder shape is theoretically studied on the basis of the macrospin model. It is found that an application of voltage pulse can induce the precessional switching of magnetization even at zero-bias magnetic field, which is of substantial importance for device applications such as voltage-controlled nonvolatile memory. Analytical expressions of the conditions for precessional switching are derived.

قيم البحث

اقرأ أيضاً

We consider a magnetic moment with an easy axis anisotropy energy, switched by an external field applied along this axis. Additional small, time-independent bias field is applied perpendicular to the axis. It is found that the magnets switching time is a non-monotonic function of the rate at which the field is swept from up to down. Switching time exhibits a minimum at a particular optimal sweep time. This unusual behavior is explained by the admixture of a ballistic (precessional) rotation of the moment caused by the perpendicular bias field in the presence of a variable switching field. We derive analytic expressions for the optimal switching time, and for the entire dependence of the switching time on the field sweep time. The existence of the optimal field sweep time has important implications for the optimization of magnetic memory devices.
We report the intrinsic critical current density (Jc0) in current-induced magnetization switching and the thermal stability factor (E/kBT, where E, kB, and T are the energy potential, the Boltzmann constant, and temperature, respectively) in MgO base d magnetic tunnel junctions with a Co40Fe40B20(2nm)/Ru(0.7-2.4nm)/Co40Fe40B20(2nm) synthetic ferrimagnetic (SyF) free layer. We show that Jc0 and E/kBT can be determined by analyzing the average critical current density as a function of coercivity using the Slonczewskis model taking into account thermal fluctuation. We find that high antiferromagnetic coupling between the two CoFeB layers in a SyF free layer results in reduced Jc0 without reducing high E/kBT.
74 - Ya. B. Bazaliy 2011
We consider a switching of the magnetic moment with an easy axis anisotropy from an up to a down direction under the influence of an external magnetic field. The driving field is applied parallel to the easy axis and is continuously swept from a posi tive to a negative value. In addition, a small constant perpendicular bias field is present. It is shown that while the driving field switches the moment in a conventional way, the perpendicular field creates an admixture of the precessional (ballistic) switching that speeds up the switching process. Precessional contribution produces a non-monotonic dependence of the switching time on the field sweep time with a minimum at a particular sweep time value. We derive an analytic expressions for the optimal point, and for the entire dependence of the switching time on the field sweep time. Our approximation is valid in a wide parameter range and can be used to engineer and optimize of the magnetic memory devices.
Current induced spin-orbit torques driven by the conventional spin Hall effect are widely used to manipulate the magnetization. This approach, however, is nondeterministic and inefficient for the switching of magnets with perpendicular magnetic aniso tropy that are demanded by the high-density magnetic storage and memory devices. Here, we demonstrate that this limitation can be overcome by exploiting a magnetic spin Hall effect in noncollinear antiferromagnets, such as Mn3Sn. The magnetic group symmetry of Mn3Sn allows generation of the out-of-plane spin current carrying spin polarization induced by an in-plane charge current. This spin current drives an out-of-plane anti-damping torque providing deterministic switching of perpendicular magnetization of an adjacent Ni/Co multilayer. Compared to the conventional spin-orbit torque devices, the observed switching does not need any external magnetic field and requires much lower current density. Our results demonstrate great prospects of exploiting the magnetic spin Hall effect in noncollinear antiferromagnets for low-power spintronics.
174 - L. Grenet , M. Jamet , P. Noe 2009
In this letter, we show efficient electrical spin injection into a SiGe based textit{p-i-n} light emitting diode from the remanent state of a perpendicularly magnetized ferromagnetic contact. Electron spin injection is carried out through an alumina tunnel barrier from a Co/Pt thin film exhibiting a strong out-of-plane anisotropy. The electrons spin polarization is then analysed through the circular polarization of emitted light. All the light polarization measurements are performed without an external applied magnetic field textit{i.e.} in remanent magnetic states. The light polarization as a function of the magnetic field closely traces the out-of-plane magnetization of the Co/Pt injector. We could achieve a circular polarization degree of the emitted light of 3 % at 5 K. Moreover this light polarization remains almost constant at least up to 200 K.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا