Magnetism in UCo0.88Ru0.12Ge Studied by Polarized Neutrons
M. Vališkaa, J.Pospíšila, G. Nénertb, A. Stunaultb, K. Prokešc, V. Sechovskýa
aFaculty of Mathematics and Physics, Charles University, DCMP, Ke Karlovu 5, CZ-12116 Praha 2, Czech Republic
bInstitut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble, France
cHZB Berlin, Hahn-Meitner Platz 1 14109 Berlin, Germany
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UCoGe is an archetype of coexisting weak itinerant 5f-electron ferromagnetism (TC ~ 3 K, μs=0.03μB/f.u.) and superconductivity (TSC ~ 0.6 K) at ambient pressure. The Ru substitution for Co leads to an initial sharp increase of the TC up to the maximum of TC=8.5 K for x=0.12, increase of spontaneous magnetic moment and suppression of superconductivity. We have grown the UCo0.88Ru0.12Ge single crystal and studied magnetization along the principal crystallographic axes. To see the microscopic background of these findings we performed a polarized neutron diffraction experiment on D3 diffractometer in ILL. We have found that the Co and U moments are parallel in UCo0.88Ru0.12Ge, in contrast to the antiparallel configuration in UCoGe. This is probably the reason of the spontaneous magnetization increase with Ru doping.

DOI: 10.12693/APhysPolA.126.330
PACS numbers: 74.70.Tx, 61.05.fm, 75.25.-jr