Topological Magnetic Hysteresis in Single Crystals of CeAgSb2 Ferromagnet

Abstract

Closed-topology magnetic domains are usually observed in thin films and in an applied magnetic field. Here we report the observation of rectangular cross-section tubular ferromagnetic domains in thick single crystals of CeAgSb2 in zero applied field. Relatively low exchange energy, small net magnetic moment, and anisotropic in-plane crystal electric fields 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 a dendritic open-topology pattern. This transition between closed and open topologies results in a "topological magnetic hysteresis" - the actual hysteresis in magnetization, not due to the imperfections and pinning, but due to the difference in the pattern morphology. Similar physics was suggested before in pure type-I superconductors and is believed to be a generic feature of other nonlinear multi-phase systems in the clean limit.

References in corpus (6)

• The Suprafroth (Superconducting Froth)
• Topological Hysteresis in the Intermediate State of Type-I Superconductors
• Probing fractal magnetic domains on multiple length scales in Nd2Fe14B
• Meissner-London susceptibility of superconducting right circular cylinders in an axial magnetic field
• Meissner-London state in anisotropic superconductors of cuboidal shape
• Magnetic field-induced softening of spin waves and hard-axis order in Kondo-lattice ferromagnet CeAgSb${}_2$

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