Superconductivity in LuxZr1-xB12 Dodecaborides with Cage-Glass Crystal Structure
N. Sluchankoa,b, A. Azarevicha, A. Bogach a, S. Gavrilkin c, V. Glushkova,b, S. Demisheva,b, K. Mitsen c, N. Shitsevalova d, V. Filippov d, S. Gabani e, and K. Flachbart e
aProkhorov General Physics Institute, RAS, Vavilov Str. 38, 119991 Moscow, Russia
bMoscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudnyi, Russia
cLebedev Physical Institute RAS, Leninskii av. 53, 119991 Moscow, Russia
dFrantsevich Institute for Problems of Materials Science, NASU, Krzhizhanovskii Str. 3, 03680 Kiev, Ukraine
eInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia
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We probed the evolution of the superconducting transition temperature Tc and the normal state parameters of LuxZr1-xB12 solid solutions employing resistivity, heat capacity and magnetization measurements. In these studies of high-quality single crystals it was found that there are two types of samples with different magnetic characteristics. An unusually strong suppression of superconductivity in LuxZr1-xB12 with a rate dTc/dx=0.21 K/at.% of Lu was observed previously on the first "magnetic" set of crystals, and it was argued to be caused by the emergence of static spin polarization in the vicinity of non-magnetic lutetium ions. On the contrary, the second (current) set of "nonmagnetic" crystals demonstrates a conventional Tc(x) dependence with a rate dTc/dx=0.12 K/at.% of Lu which is typical for BCS-type superconductors doped by nonmagnetic impurities. The reason for this difference is yet unclear. Moreover, the H-T phase diagram of the superconducting state of LuxZr1-xB12 (0 ≤ x ≤1) solid solutions has been deduced from magnetization measurements.

DOI: 10.12693/APhysPolA.131.1036
PACS numbers: 74.25.-q, 74.62.Bf, 74.70.Ad