Using a custom-FPGA architecture to extend the scale of atomistic magnetic spin simulations

Probing Exchange Bias Effects in CoO/Co Bilayers with Pillar-Like CoO Structures

“…Although Co/CoO is the oldest known exchange bias system, 17) the past decade has revealed numerous new aspects regarding the advantageous role of structural disorder on the exchange bias at Co/CoO interfaces. [18][19][20][21][22][23][24] In pioneering work, it was shown that the deliberate introduction of non-magnetic structural-defects into highly-crystalline epitaxial thin films of Co/CoO via dilution of the antiferromagnet with non-magnetic atoms such as Zn, 20) or by deliberate crystal twinning, 21) enhanced exchange bias by assisting the formation of dilute-antiferromagnetic thermal remnant magnetization, 22,23) in accordance with the predictions of the atomistic domain state model (DSM). 24,25) It is worth noting that in that body of work, the absolute maximum exchange bias recorded for such MBE-grown $20 nm thick Co/CoO films was 700 Oe at 5 K, 21) whereas all of our thicker $60 nm sputtered films have a comparable exchange bias at 200 K, suggesting a higher blocking temperature and interfacial energy.…”

Collective nonlinear electric polarization via defect-driven local symmetry breaking

“…45,46 In the model, the microscopic dipole undergoes reorientation to minimize their energies in the internal field according to a standard heat bath algorithm. 47 The energy of the dipole system has four main components…”