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Unusual ferromagnetic domains in CeAgSb₂

Ruslan Prozorov, Sergey Bud'ko and Paul Canfield

Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, Iowa 50011

April 2008

Abstract

Closed topology magnetic domains are usually observed in thin films and in applied magnetic field. Here we report observation of tubular ferromagnetic domains in thick single crystals of CeAgSb₂ in zero applied field. Relatively low exchange energy, small ordered magnetic moment and peculiarities of crystal electric field induced magnetic anisotropies lower the domain wall energy and allow for the formation of the closed-topology patterns. Upon cycling the magnetic field, the domain structure irreversibly transforms into various open topology patterns. This transition between closed and open topologies results in “topological hysteresis” – actual hysteresis in magnetization, not due to imperfections and pinning, but due to difference in pattern geometry. Similar physics is observed in pure type-I superconductors and other highly nonlinear systems with phase separation.

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Following the magnetization loop at T=5 K

Warming up after completing the loop (from remanent state)

© Ruslan Prozorov

Last updated: April 12, 2008 8:32 AM