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| VOLUME 107 (2018) | ISSUE 8 | PAGE 497 |
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Dynamics of heavy carriers in the ferromagnetic superconductor UGe2
V. G. Storchaka, J. H. Brewerb, D. G. Eshchenkoc, P. W. Mengyand,e, O. E. Parfenova, A. M. Tokmacheva
aNational Research Center "Kurchatov Institute", 123182 Moscow, Russia bDepartment of Physics and Astronomy, University of British Columbia, BC V6T 1Z1, Vancouver, Canada cBruker BioSpin AG, Industriestrasse 26, 8117 Fällanden, Switzerland dDepartment of Physics, Northern Michigan University, Marquette, 79409-1051 Michigan, USA eDepartment of Physics, Texas Tech University, Lubbock, 79409-1051 Texas, USA
Abstract
Superconductivity and ferromagnetism in a number of uranium-based materials come from the same f-electrons with a relatively large effective mass, suggesting the presence of a band of heavy quasiparticles, whose nature is still a mystery. Here, UGe2 dynamics in both ferromagnetic and paramagnetic phases is studied employing high-field μ +SR spectroscopy. The spectra exhibit a doublet structure characteristic to formation of subnanometer-sized magnetic polarons. This model is thoroughly explored here and correlated with the unconventional physics of UGe2. The heavy-fermion behaviour is ascribed to magnetic polarons; when coherent they form a narrow band, thus reconciling heavy carriers with superconductivity and itinerant ferromagnetism. |