Superconductivity, negative magnetoresistance, and anisotropy of the conductivity of YFe4Al8 and ScFe4Al8 single crystals in the frequency range 0–108 Hz

Abstract

The anisotropy of the electrical resistivity of YFe4Al8 and ScFe4Al8 single crystals is investigated for the first time in the frequency range 0–108 Hz and temperature range 300–4.2 K. It is found that the conductivity is higher along the growth axis of the crystals than in the perpendicular direction, while the parameters governing the antiferromagnetic ordering, negative magnetoresistance, and superconductivity effects observed in these single crystals are isotropic. Some effects known previously for polycrystalline high-Tc superconductors containing magnetic impurities are observed in the single crystals investigated and are found to be anisotropic in them.

Possible coexistence of antiferromagnetism, spin–glass, and superconductivity in ScFe 4 Al 8 , and YFe 4 Al 8 single crystals

“…3a the temperature dependence of the electrical resistivity, ρ(T), for ScFe 4 Al 8 and YFe 4 Al 8 single crystals in the vicinity of "partial" superconducting transition (T = 4-7 K) is shown. The electrical resistivity is measured along the direction of single crystal growth and zero magnetic field and in 50 Oe [1]. It is seen that the magnetic field of 50 Oe destroys superconductivity.…”

“…The anomaly at 60 K does not appear clearly in the temperature dependence of magnitude of the magnetic satellites (ND) [4]. In [1] the temperature dependence of the electrical resistivity, ρ(T), of ScFe 4 Al 8 and YFe 4 Al 8 single crystals show in the 25-55 K region a peak in the ρ(T) plot, which is damped by a low magnetic field of 50 Oe. Therefore, in the above mentioned temperature range the effect of the negative magnetoresistivity is observed.…”

“…A "fractional" superconductivity which exits in a fraction of compound's volume only, has recently been reported for some ThMn 12 -type ternaries of rare earths at low temperature (for references see [1]). For the other hand, the compounds of nonmagnetic rare earths exhibiting, in principle, antiferromagnetic character, show complex magnetic properties at low temperature (see e.g.…”

Negative magnetoresistivity of the RM4Al8 (R=Sc, Y, Ce, Yb, Lu; M=Cr, Mn, Fe) ternaries with the ThMn12-type crystal structure

“…The contactless resonator method for examination of the surface electrical resistivity, R s in a wide temperature range (4.2-300 K) was used [9][10][11]13]. The electrical surface resistance of the polycrystalline CeFe 4 Al 8 , ScFe 4 Al 8 , LuFe 4 Al 8 , YCr 4 Al 8 , CeCr 4 Al 8 and YMn 4 Al 8 samples was examined at the frequency of 30 MHz, whereas that of the single crystals of ScFe 4 Al 8 and YFe 4 Al 8 at the frequency of 45 MHz.…”

“…Lately, the authors of Refs. [9][10][11] have discovered the new class of materials with the NM-the ternaries of the RM 4 Al 8 -type (where R-nonmagnetic lanthanide element or also Y and Sc, M-transition metal). These compounds exhibit the tetragonal body centered structure of the ThMn 12 -type presented in Fig.…”