Ultrahigh density vertical magnetoresistive random access memory (invited)

Abstract

In this paper, we present the vertical magnetoresistive random access memory (VMRAM) design based on micromagnetic simulation analysis. The design utilizes the vertical giant magnetoresistive effect of the magnetic multilayer. By making the memory element into a ring-shaped magnetic multilayer stack with orthogonal paired word lines, magnetic switching of the memory device becomes very robust. The design also adopts the readback scheme in pseudo spin valve MRAM so that only one transistor is needed for each bit line which can connect hundreds of memory elements, yielding a very high area density. It is estimated that the ultimate area density for the VMRAM is 400 Gbits/in.2. It is suggested that this memory design has the potential to not only replace the present semiconductor memory devices, such as FLASH, but also the potential to replace DRAM, SRAM, and even disk drives.

Off‐axis electron holography of magnetic nanowires and chains, rings, and planar arrays of magnetic nanoparticles

“…Such rings are appealing candidates for high-density information storage applications because they are expected to form chiral domain states that exhibit flux closure (FC). Such FC states were used in early data storage applications involving ferrite cores, and have recently been proposed as elements in novel device architectures for magnetoresistive random-access memory (e.g., Zhu et al, 2000). Nanoparticle rings are also of interest for the development of electron holography because their magnetization directions cannot be reversed through the application of in-plane fields.…”

Calixarene‐Encapsulated Nanoparticles: Self‐Assembly into Functional Nanomaterials

“…61 Interest in magnetic rings has recently resurfaced as potential switching elements in devices based on magnetoresistive random-access memory (MRAM). 62 Co rings as small as 100 nm across have been fabricated by electron-beam lithography, 63 but further miniaturization is limited by the present resolution afforded by ''top-down'' methodologies.…”

Vortex core size in interacting cylindrical nanodot arrays

“…[9] In particular, two-dimensional arrays of magnetic nanoparticles have been proposed as candidates for magnetoresistive random access memory (MRAM) devices. [10,11,12] Recent studies on such structures have been carried out with the aim of determining the stable magnetized state as a function of the geometry of the particles. [3,4,13,14,15,16] In the case of cylindrical particles, three idealized characteristic configurations have been identified: ferromagnetic with the magnetization parallel to the basis of the cylinder, ferromagnetic with the magnetization parallel to the cylinder axis, and a vortex state in which most of the magnetic moments lie parallel to the basis of the cylinder.…”