Memory-bit selection and recording by rotating fields in vortex-core cross-point architecture

In one of our earlier studies S.-K. Kim et al., [Appl. Phys. Lett. 92, 022509 (2008)], we proposed a concept of robust information storage, recording, and readout, which can be implemented in nonvolatile magnetic random-access memories and is based on the energetically degenerated twofold ground states of vortex-core magnetizations. In the present study, we experimentally demonstrate reliable memory-bit selection and recording in vortex-core cross-point architecture, specifically using a two-by-two vortex-state disk array. In order to efficiently switch a vortex core positioned at the intersection of crossed electrodes, two orthogonal addressing electrodes are selected, and then two Gaussian pulse currents of optimal pulse width and time delay are applied. Such tailored pulse-type rotating magnetic fields which occur only at the selected intersection are a prerequisite for a reliable memory-bit selection and low-power-consumption recording of information in the existing cross-point architecture. (C) 2011 American Institute of Physics. [doi:10.1063/1.3551524]