Exchange-biased magnetic tunnel junctions and application to nonvolatile magnetic random access memory (invited)

Abstract

Dynamic state switching in nonlinear multiferroic cantilevers Appl. Phys. Lett. 101, 043506 (2012) Nanomagnetism of cobalt ferrite-based spin filters probed by spin-polarized tunneling Appl. Phys. Lett. 101, 042409 (2012) Magnetic Schottky diode exploiting spin polarized transport in Co/p-Si heterostructure Appl. Phys. Lett. 100, 262402 (2012) Concepts and steps for the realization of a new domain wall based giant magnetoresistance nanowire device: From the available 24 multiturn counter to a 212 turn counter Exchange biased magnetic tunnel junction ͑MTJ͒ structures are shown to have useful properties for forming magnetic memory storage elements in a novel cross-point architecture. MTJ elements have been developed which exhibit very large magnetoresistive ͑MR͒ values exceeding 40% at room temperature, with specific resistance values ranging down to as little as ϳ60 ⍀͑m͒ 2 , and with MR values enhanced by moderate thermal treatments. Large MR values are observed in magnetic elements with areas as small as 0.17 ͑m͒ 2 . The magnetic field dependent current-voltage characteristics of an MTJ element integrated with a silicon diode are analyzed to extract the MR properties of the MTJ element itself.

Training effect of exchange bias inγ−Fe2O3coatedFeZheng1, Wen2, Fung3 et al. 2004Phys. Rev. B1064640View full textAdd to dashboardCite

“…Exchange bias effect has been intensively studied both theoretically and experimentally due to its extensive applications in magnetic sensors and data storage. 3,4 However, up to now, there has not been a theoretical model 1,5 that can account for all the diverse experimental results. 1,2 One of the interesting characteristics of exchange bias is that it shows a strong dependence on the thermal and magnetic histories.…”

Angle-DependentNi2+X-Ray Magnetic Linear Dichroism: Interfacial Coupling Revisited

“…For example, magnetic tunnel junctions used in magnetic random access memory [1] consist of two ferromagnetic layers with significantly different reversal fields separated by a thin insulating layer [2]. Exchange biased systems in which unidirectional anisotropy is induced in a ferromagnetic layer by an adjacent antiferromagnetic layer have found widespread use in read heads of hard drives [3].…”

Anomalous Bias Dependence of Spin Torque in Magnetic Tunnel Junctions

“…Thus, CIMS provides a powerful new tool for the study of spin transport in magnetic nanostructures. In addition, it offers the intriguing possibility of manipulating high-density nonvolatile magnetic-device elements, such as magnetoresistive random access memory (MRAM), without applying cumbersome magnetic fields [10].While the fundamental physics underlying the spin transfer torque (STT) in spin valves has been extensively studied theoretically [1,[11][12][13], its role in MTJs remains an unexplored area thus far, except for the pioneering work of Slonczewski [2,3], who employed the free-electron model in the low bias regime. One of the most pressing needs is a comprehensive understanding of the bias dependence of the STT in MTJs, which will be important for the development of MRAM that uses CIMS for writing the magnetic memory cell.…”