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The present experiments indicate that the phenomena of inverse exchange bias and negative magnetization are observed simultaneously in Gd2Co0.5Mn1.5O6 below the ferrimagnetic compensation point Tcomp. The training effect confirms the intrinsic nature of the inverse exchange bias and reveals that the frozen spins relax more slowly than the rotatable spins according to the fitting of exchange bias field (HEB) vs cycle loops (n) curve. The amplitude of HEB varies inversely with the cooling field Hcool and the inverse exchange bias is found to remain up to 50 kOe. The observed exchange bias is argued to be due to the fact that the inverse ferromagnetic moments below Tcomp can be flipped by adjusting the amplitude or direction of the magnetic field during the M(H) hysteresis loop measurement. The manipulability of the negative magnetization state is demonstrated by the remanent magnetization and magnetic switching measurements. [ABSTRACT FROM AUTHOR]

The magnetic radial vortex is a nanoscale magnetization configuration that is typically stabilized by the interfacial Dzyaloshinskii–Moriya interaction (i-DMI). The existing control methods for the radial vortex core polarity rely on the use of current flow or magnetic fields, which may cause long consumption times or limit device miniaturization. Here, we investigate a repeated reversal of a radial vortex that can be driven by strain from a piezoelectric substrate using micromagnetic simulations. A phase diagram for the representative regions against perpendicular anisotropy, i-DMI, and the applied strain was obtained. The derived phase diagram was used to associate the mechanism of the core reversal with edge magnetization rotation during core magnetization switching, which exhibits a relationship by transforming a quasi-Bloch wall into a Néel wall. The existence of the i-DMI effect causes the core polarity and radial chirality of the radial vortex to be reversed simultaneously without resulting in larger core movements. These results offer an alternative and efficient way to achieve core reversal, which is expected to stimulate the radial vortex application in magnetoresistive memory devices. [ABSTRACT FROM AUTHOR]