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arXiv · 1503.08380

Cooperative Multiscale Aging in a Ferromagnet/Antiferromagnet Bilayer

Sergei Urazhdin
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Abstract

We utilize anisotropic magnetoresistance to study temporal evolution of the magnetization state in epitaxial Ni$_{80}$Fe$_{20}$/Fe$_{50}$Mn$_{50}$ ferromagnet/antiferromagnet bilayers. The resistance exhibits power-law evolution over a wide range of temperatures and magnetic fields, indicating that aging is characterized by a wide range of activation time scales. We show that aging is a cooperative process, i.e. the magnetic system is not a superposition of weakly interacting subsystems characterized by simple Arrhenius activation. The observed effects are reminiscent of avalanches in granular materials, providing a conceptual link to a broad class of critical phenomena in other complex condensed matter systems.

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Sergei Urazhdin. 2015-03-29. Cooperative Multiscale Aging in a Ferromagnet/Antiferromagnet Bilayer. https://doi.org/10.1103/physrevb.92.174416

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