The Physics of Spin-Transfer Torque Switching in Magnetic Tunneling Junctions in Sub-10 nm Size Range

Anomalous Properties of Sub-10-nm Magnetic Tunneling Junctions

“…shown. The 3D device clearly yields a multilevel operation with a switching current density comparable to values published elsewhere in the sub-20nm range (~3MA/cm 2 ) [48,60].…”

“…The measured switching current was around 0.6uA and a TMR of 60%. The current density is approximately ~1MA/cm 2 [48]. This is comparable to what was measured with the nanoprobe, and is smaller than what would have been predicted by linear scaling.…”

“…This field has been further augmented with the discovery of the TMR effect, expanding the theoretical capability of magnetics to move beyond memory storage and onto information processing (MRAM). Magnetic based information processing yet remains a niche role and cannot dominate the market unless the switching energy is brought down substantially[48].A magnetic tunnel junction (MTJ) is simply defined as two ferromagnetic electrodes separated by an ultra-thin oxide. Tunneling is strictly a quantum mechanical effect where a particle tunnels through a barrier which would otherwise be impossible to transverse according to classical mechanics.…”

3D multilevel spin transfer torque devices

“…The STT switching current density on the order of 3 MA/cm 2 was comparable to the values in typical sub-20-nm single-junction MTJs as reported elsewhere. 19,[37][38][39] It can be noted that for this particular geometry and parameters' setup, the states in which both junctions have antiparallel spins (AP/AP) exist only in a relatively narrow voltage range ($3 mV) or, in other words, these states are not relatively stable for this particular set of coercivity fields. However, it should be understood that if necessary, this state can be made as stable as the other layers by increasing its coercivity, as explained below in more detail.…”

Nanofabrication and Spectroscopy of Magnetic Nanostructures Using a Focused Ion Beam

“…This domination of surface effects is because of collective spin excitations. As a result, the spin relaxation time can be substantially increased in this case [60]. Size dependence of the switching current density Green dots show the theoretical points, red dots are the data from literature and black dots resulted from the fib prototyping [60] Different approaches have been proposed in order to perform the study in sub 10nm range and a couple of them will be discussed.…”