Magnetoelectric switching energy in Cr₂O₃/Pt/Co perpendicular exchange coupled thin film system with small Cr₂O₃magnetization

Abstract

We investigated perpendicular exchange bias switching by a magnetoelectric field cooling process in a Pt-spacer-inserted Cr2O3/Co exchange-coupled system exhibiting small Cr2O3 magnetization. Although higher magnetoelectric switching energies with decreasing Cr2O3 thickness due to the exchange bias were reported in Cr2O3/Co all-thin-film systems, in this study, we demonstrated low-energy switching in a magnetoelectric field cool process regardless of the exchange-bias magnitude; we balanced the exchange-bias energy with the Zeeman energy associated with finite magnetization in Cr2O3. We proposed a guideline for realizing low-energy switching in thin Cr2O3 samples.

Manipulation of Antiferromagnetic Spin Using Tunable Parasitic Magnetization in Magnetoelectric Antiferromagnet

“…However, the additional Zeeman energy of M Cr2O3 in doped Cr 2 O 3 can compensate and minimize the energy barrier, which results in a reduction in the switching electric field. Recently, a reduction in the switching electric field by using the Zeeman energy of accidentally obtained M Cr2O3 was demonstrated for an undoped Cr 2 O 3 /Co system; however, this effect was applicable only for the thick Cr 2 O 3 region (≈1000 nm) because the magnitude of M Cr2O3 is small and uncontrollable. In this work, we considered the influence of tunable parasitic magnetization on electrical switching based on the E th versus 1/ H fr plot in the ME field cooling (MEFC) processes .…”

“…Figure shows the E th versus 1/ H fr plot for exchange bias switching in an MEFC process for the Al 0.07%‐doped and Ir 0.07%‐doped samples (Al 2 O 3 /Pt 25/doped Cr 2 O 3 1000/Pt 1.3/Co 1/Pt 5 [nm]). The plot for undoped sample is also shown in Figure . The plots represent the threshold electric field for exchange bias switching ( E th ) at a certain freezing magnetic field, H fr .…”

Magnetoelectric Switching Energy of Antiferromagnetic Cr2O3 Used for Spintronic Logic Devices and Memory

“…The E lt (or E rt ) to 1/ H obtained from a ME switching of AFM Cr 2 O 3 and its perpendicular exchange‐coupling systems is typically used as a linear relation fit for describing the ME switching energy. [ 19–24,31 ] However, no consensus has been reached on explaining the physical meaning of the obtained linear line, especially for the intercept.…”

Multiferroic heterostructures for spintronics

“…Electric-field-driven switching of this configuration was first demonstrated in bulk crystals with out-of-plane ferromagnet (Co/Pt)n, however it required a static magnetic field to achieve full switching of the surface magnetization [101,105]. Linear magnetoelectric switching is defined by a critical energy product of electric field and magnetic field [10], meaning magnetoelectric switching of Cr2O3 requires either substantial static magnetic fields [106,107] or extraordinarily large voltages. This presents a significant engineering challenge for scaling of devices, as a Cr2O3 thin film must be able to withstand voltages large enough for switching, and significant work is currently focused on increasing the breakdown voltage or decreasing the switching threshold for thin films [108,109].…”

“…This presents a significant engineering challenge for scaling of devices, as a Cr2O3 thin film must be able to withstand voltages large enough for switching, and significant work is currently focused on increasing the breakdown voltage or decreasing the switching threshold for thin films [108,109]. Thus far, magnetoelectric switching in thin film heterostructures has required substantial magnetic fields on the order of ~0.6-1 T [93,106,107], but the technology remains promising for scale multiferroic devices.…”