Superconductivity and Magnetism of Dy1-x YxRh4B4: Candidate for Spin-Triplet Cooper Pairing

V.M. Dmitriev a, b, A.J. Zaleski c, E.P. Khlybov a, d, L.F. Rybaltchenko b, E.V. Khristenko b, L.A. Ishchenko b and A.V. Terekhov b a International Laboratory of High Magnetic Fields and Low Temperatures, Wrocław, Poland b B. Verkin Institute for Low Temperature Physics and Engin., of the NAS of Ukraine, Kharkov, Ukraine c Institute of Low Temperature and Structure Research, PAS, Wrocław, Poland d Institute for High Pressure Physics, RAS, Troitsk, Russia

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Received: 6 11 2007;

In this work for the first time we give the evidence that compound Dy1-xYx Rh4B4 with the tetragonal body-centered crystal structure LuRu4B4 is the ferrimagnetic at temperatures TCur < 40 K, ferrimagnetic superconductor at TC < 10 K and antiferromagnetic superconductor at TN < 3 K. No reentrant behavior was found down to T = 0.32 K. For the first time by means of a method of microcontact spectroscopy of the Andreev reflection in point contact Ag-Dy0.8Y0.2Rh4B4 the value and temperature and field dependences of superconducting gap parameter Δ(T, H) in Dy0.8Y0.2Rh4B4 were determined. The value of the ratio 2 Δ(0)/kTC is about 4. Some unusual features of Δ(T, H) dependences were observed, which give the evidence that the Dy1-xYxRh4B4 is a candidate for spin-triplet Cooper pairing of charges with the parallel spins.

DOI: 10.12693/APhysPolA.114.83 PACS numbers: 74.70.Ad