Octonary Resistance States in La_0.7Sr_0.3MnO₃/BaTiO₃/La_0.7Sr_0.3MnO₃ Multiferroic Tunnel Junctions

Abstract

General drawbacks of current electronic/spintronic devices are high power consumption and low density storage. A multiferroic tunnel junction (MFTJ), employing a ferroelectric barrier layer sandwiched between two ferromagnetic layers, presents four resistance states in a single device and therefore provides an alternative way to achieve high density memories. Here, an MFTJ device with eight nonvolatile resistance states by further integrating the design of noncollinear magnetization alignments between the ferromagnetic layers is demonstrated. Through the angle‐resolved tunneling magnetoresistance investigations on La0.7Sr0.3MnO3/BaTiO3/La0.7Sr0.3MnO3 junctions, it is found that, besides collinear parallel/antiparallel magnetic configurations, the MFTJ shows at least two other stable noncollinear (45° and 90°) magnetic configurations. Combining the tunneling electroresistance effect caused by the ferroelectricity reversal of the BaTiO3 barrier, an octonary memory device is obtained, representing potential applications in high density nonvolatile storage in the future.

Prospects of spintronics based on 2D materials

“…MFTJ and related physics of multiferroic junctions have been actively investigated both theoretically and experimentally . Recently, it was demonstrated that by further considering noncollinear magnetization alignments between the FM layers, MFTJ device with eight nonvolatile resistance states can be realized . MFTJ opens a new pathway toward low power and higher density nonvolatile memory.…”

Bi-ferroic memristive properties of multiferroic tunnel junctions

“…Although MTJs have been the subject of intensive study due to their great potential for non-volatile magnetic memory applications, 1-3 moderate data storage density and especially a high-power consumption for controlling magnetisation still remain major challenges. To tackle those problems, several methods have been proposed including but not limited to utilising various non-collinear magnetization configurations in the ferromagnetic electrodes of semiconductor spin valves 4 or all-oxide MTJs, 5 manipulating domain states of ferromagnetic electrodes in pseudo spin valves, 6 or tuning tunnel barrier oxygen vacancies by voltage pulses in MgO-based MTJs. 7 Despite the aforementioned solutions, one promising candidate is multiferroic tunnel junctions (MFTJs), in which the ferroelectric/multiferroic layer is incorporated into a conventional magnetic tunnel junction (MTJ) as the tunnel barrier.…”

Interface Engineering and Emergent Phenomena in Oxide Heterostructures

“…If the spacer is not just a common insulator but a ferroelectric layer, the tunneling current will be controlled not only by magnetic field with different spin configurations, but also the applied electric bias that modifies the tunneling barrier by switching the polarization of the ferroelectric spacer . In this case, four states, or even more nonvolatile states, can be achieved at room temperature, which is important for designing novel high‐density information storage devices.…”