Superconductivity and Magnetism of $Dy_{1-x}Y_xRh_4B_4$: Candidate for Spin-Triplet Cooper Pairing

In this work for the first time we give the evidence that compound $Dy_{1-x}Y_x Rh_4B_4$ with the tetragonal body-centered crystal structure $LuRu_4B_4$ is the ferrimagnetic at temperatures $T_{Cur}$<40 K, ferrimagnetic superconductor at $T_C$ <10 K and antiferromagnetic superconductor at $T_N$ <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-Dy_{0.8}Y_{0.2}Rh_4B_4$ the value and temperature and field dependences of superconducting gap parameter∆(T, H) in $Dy_{0.8}Y_{0.2}Rh_4B_4$ were determined. The value of the ratio 2∆(0)/k$T_C$ is about 4. Some unusual features of∆(T, H) dependences were observed, which give the evidence that the $Dy_{1-x}Y_xRh_4B_4$ is a candidate for spin-triplet Cooper pairing of charges with the parallel spins.