Crystal chemistry and physical properties of the nonmagnetic Kondo compound HfAs1.7Se0.2.
Single crystals of HfAs(1.7)Se(0.2) are grown by chemical transport reaction and their chemical composition characterized in detail by various analytical methods. Chemical analyses and crystal structure investigations by single-crystal X-ray diffraction as well as powder diffraction with synchrotron radiation reveal a tetragonal PbFCl structure type with strong disorder caused by a significant arsenic deficiency (As(0.9)) on the 2a site and mixed occupancy of the 2c site (As(0.8)Se(0.2)). HfAs(1.7)Se(0.2) is a diamagnetic metal which transforms into a superconducting state at T(c)=0.52 K. Similar to other PbFCl-type arsenide selenides, the title compound displays a magnetic-field-independent -AT(1/2) term in the low-temperature electrical resistivity. This unusual term presumably originates from the electron scattering of structural two-level systems. According to the experimental results, HfAs1.7Se0.2 appears to be a rare example of a nonmagnetic Kondo material.
Czulucki
Andreas
A
Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, Dresden, Germany. andreas.czulucki@cpfs.mpg.de
Auffermann
Gudrun
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Bednarski
Michal
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Bochenek
Łukasz
Ł
Böhme
Maik
M
Cichorek
Tomasz
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Niewa
Rainer
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Oeschler
Niels
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Schmidt
Marcus
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Steglich
Frank
F
Kniep
Rüdiger
R