Magnetoresistance of conductive filament in Ni/HfO₂/Pt resistive switching memory

Abstract

Ferromagnetic conductive filaments (CFs) were formed in a conductive-bridge random access memory (CBRAM) with a Ni electrode using high current compliances during a set process. We investigated CFs in a Ni/HfO2/Pt CBRAM using the current compliance dependences of the set process, low-temperature characteristics, and anisotropic magnetoresistance (AMR). Set processes occurred when a positive bias was applied to the Ni electrode only; therefore, the switching phenomena showed polarity. The resistance of the ON state (low resistance state) was dependent on the current compliance between 2 and 5 mA. The ON state of the device showed a metallic conduction property, suggested by the temperature dependence of resistance. When a high current compliance (5 mA) was used for programming, the ON state showed AMR, which was direct evidence of ferromagnetic CF formation. This suggests that the formation of a ferromagnetic CF is associated with the accumulation of Ni ions that diffused from the Ni electrode. The OFF-state (high resistance state) resistance slightly increased with decreasing temperature and AMR was not observed.

Nanoscale magnetization reversal by electric field-induced ion migration

“…10(e)]. [29,30] This is consistent with the fact that AMR occurred in ferromagnetic transition metal depends strongly on the direction of the magnetization with respect to the electric current direction. [57,58] By rotating the direction of the out-of-plane magnetic field with respect to the substrate surface with a fixed magnitude of 2 T in the LRS of the Co/ HfO 2 /Pt device [ Fig.…”

“…10(a) and 10(b)]. [29][30][31] It is found that the Ni/ TiO 2 /Pt device shows convexity in its AMR plot when the direction of the magnetic field is perpendicular to the direction electric current flowing across the device [Figs. 10(c) and 10(d)], whereas a concavity is observed when the magnetic field is aligned in the direction parallel to that of the device currents [ Fig.…”

“…[21,22,[25][26][27] In addition to modulating the magnetization through electrical field-induced ion migration and redistribution, the formation of foreign magnetic conductive filament via the ionization and injection of Co 3+ and Ni 2+ ions from electrochemically active ferromagnetic metal electrodes can also generate tunneling magnetoresistance (TMR) and anisotropic magnetoresistance (AMR) phenomena in different resistance states. [28][29][30][31] Enrichment of the bistable resistive switching characteristics of memory devices with MR behaviors allows the integration of other functions e.g., sensing and data processing into a single cell, and benefits the future breakthrough of von Neumann bottleneck issue that is faced by the modern computer systems.…”

Anisotropic Magnetoresistance of Nano-conductive Filament in Co/HfO2/Pt Resistive Switching Memory

“…Recently, the Ni CF in RRAM has been confirmed to show ferromagnetism [ 16 , 17 ]. To manipulate ferromagnetism, it is necessary to understand the magnetic structure.…”

Формирование наноразмерных ферромагнитных филаментов Ni в пленках ZrO-=SUB=-2-=/SUB=-(Y)

“…В последние годы появился повышенный интерес к возможности управления резистивным переключением (РП) в мемристорах путем совместного воздействия электрического и магнитного полей [1,2]. Данный подход обеспечивает повышенную функциональность мемристоров, позволяя за счет приложения внешнего магнитного поля изменять электросопротивление проводящего филамента в функциональном диэлектрическом слое мемристорной структуры (эффект магнетосопротивления) [3,4]. Другой подход заключается в формировании в функциональном диэлектрике филаментов, состоящих из атомов ферромагнитного материала (Fe, Co и др.)…”