Purely Antiferromagnetic Magnetoelectric Random Access Memory


Purely Antiferromagnetic Magnetoelectric Random Access Memory

Kosub, T.; Kopte, M.; Hühne, R.; Appel, P.; Shields, B.; Maletinsky, P.; Hübner, R.; Liedke, M. O.; Fassbender, J.; Schmidt, O. G.; Makarov, D.

Magnetic random access memory schemes employing magnetoelectric coupling to write binary information promise outstanding energy-efficiency. We propose and realize purely antiferromagnetic magnetoelectric random access memory (AF-MERAM) that offers a remarkable 50 times lower writing threshold compared to ferromagnet-based counterparts, is robust against magnetic disturbances and exhibits no ferromagnetic hysteresis losses. Using the magnetoelectric antiferromagnet Cr2O3, we realize reliable isothermal switching via gate voltage pulses and all-electric read-back at room temperature. As no ferromagnetic component is present in the system, the writing magnetic field does not need to be pulsed and removed for read-out allowing permanent magnets to be used. Based on our prototypes of these novel systems, we construct a comprehensive model of the magnetoelectric selection mechanism in thin films of magnetoelectric antiferromagnets. We identify that growth induced effects lead to emergent ferrimagnetism, which interferes with the linear magnetoelectric effect. After pinpointing lattice misfit as the likely origin, we provide routes to enhance or mitigate this emergent ferrimagnetism as desired. AF-MERAM cells are a general concept for antiferromagnetic spintronics and not limited to memory applications.

Keywords: Magnetoelectric Random Access Memory; Antiferromagnets; anomalous Hall magnetometry; zero-Offset Hall

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Publ.-Id: 23680