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arXiv · 1412.0086

Evidence of Dilute Ferromagnetism in Rare-Earth doped YAG

W. G. Farr·M. Goryachev·J. M. le Floch·P. Bushev·M. E. Tobar
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Abstract

This work demonstrates strong coupling regime between an Erbium ion spin ensemble and microwave Hybrid Cavity-Whispering Gallery Modes in a Yttrium Aluminium Garnet dielectric crystal. Coupling strengths of $220$~MHz and mode quality factors in excess of $10^6$ are demonstrated. Moreover, the magnetic response of high-Q modes demonstrates behaviour which is unusual for paramagnetic systems. This behaviour includes hysteresis and memory effects. Such qualitative change of the system's magnetic field response is interpreted as a phase transition of Rare Earth ion impurities. This phenomenon is similar to the phenomenon of dilute ferromagnetism in semiconductors. The clear temperature dependence of the phenomenon is demonstrated.

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W. G. Farr, M. Goryachev, J. M. le Floch, P. Bushev, M. E. Tobar. 2014-11-29. Evidence of Dilute Ferromagnetism in Rare-Earth doped YAG. https://doi.org/10.1063/1.4931432

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