Fabrication of low-dimensional superparamagnetic vanadium diselenide clusters for expanding magnetic storage capacity

Abstract

The chip performance has been improving with the process technology in recent years following the Moore's law. Their applications and necessities are in various fields such as 5G communications, Internet of Things (IoT), mining cryptocurrency and Neural network computing (NNC) for artificial intelligence (AI). However, when the processing signals are emitted from processing units and finally transferred to memories, the transferring speed is decreasing. Therefore, among all the novel research of memories, it is anticipated to develop the technology with high storage capacity and enough processing performance. From previous literature of Intel published in 2020, the technology with those characteristics is determined as warm memory. During the following years, the most distinctive technology is MRAM which utilizes magnetic materials as core technology breaking the component frame of using electric materials and impacting the developing direction of memory. But among the development of MRAM in recent years, the significant difficulties are the competition between magnetic anisotropy energy and heat in micro-size range resulting in the transition from superparamagnetism to ferromagnetism confining the smallest size in component development for MRAM. So the novel solution is utilizing the transition metal dichalcogenides (TMDs) in order to produce low dimensional applications of spintronic thin films. In this report, we utilize the TMD material, VSe2 which is firstly published as a process recipe of self-assembled zero dimensional (0D) superparamagnetic clusters. In addition, a novel mechanism called expanding magnetic technology (ExM tech.) is demonstrated by superparamagnetic VSe2/ferromagnetic Co interfaces. The 0D superparamagnetic clusters are successfully synthesized on the surface of ferromagnetic thin films. The direction of magnetization for those superparamagnetic clusters will transform from random alignment to the specific alignment along with the magnetization direction of the ferromagnetic thin films which is attributed to the pinning from the ferromagnetic thin films. Therefore, the total magnetization of magnetic thin films can be significantly enhanced in size range of angstrom by ExM tech. After million cycles of reliability examinations, the magnetic properties remain stable. This technology will be beneficial for the applications on component process which can reach the expected total magnetizations with smaller size of magnetic thin films in MRAM. Those research results give MRAM as a nvRAM great potential on the commercial production.