Low-frequency impedance and heat capacity of LuFe4Al8

Abstract

Temperature dependences of low-frequency impedance (0–107 Hz) and heat capacity of LuFe4Al8 are studied at low temperature in the intervals 4.5–300 K and 1.5–120 K, respectively. The observed singularities suggest that antiferromagnetic phase ordering occurs at TN=100.5 K. A sharp increase in the resistance is observed at a certain temperature T1<TN below which a negative magnetoresistive effect is detected in a weak magnetic field (H<50 Oe). It is shown that the low- temperature anomalies at T<25 K are associated with the superconducting transition. This is supported by the presence of the Meissner effect, levitation, a decrease in ohmic losses, as well as the influence of a static magnetic field and direct current on the resistance of the compound. A magnetostructural phase transition, which is assumed to occur at T1<TN, may be responsible for the peculiarities observed in the physical properties of LuFe4Al8.