The results of experimental investigations of the temperature dependences of the surface resistance and specific heat of ternary rare-earth compounds are presented: LuFe4Al8, ScFe4Al8, CeFe4Al8, CeCr4Al8, YFe4Al8, YCr4Al8, YMn4Al8, UCu4Al8, LaAg6In6, and PrAg6In6, which have ThMn12 structure. It is shown that at a certain temperature, characteristic for each compound with Fe, Cr, and Mn, below the Néel temperature a jump is observed in the total impedance and specific heat. At lower temperatures a negative magnetoresistance is observed in these compounds in weak magnetic fields. Superconducting phases are found in the compounds ScFe4Al8 (Tc=6 K), YCr4Al8 (Tc=4.5 K), YFe4Al8 (Tc=6 K), and PrAg6In6 (Tc=8.3 K).

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.

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The temperature dependence and concentration dependence of the heat capacity C and surface resistance Rs are measured in the compounds YNi5−xCux (x=0, 0.1, 0.2, 0.25, 0.6, and 1.25). The measured values of C(x) and Rs(x) are used to determine the concentration dependence of the density of states N(E,x). A maximum is observed on N(E,x) at x=0.2. The results constitute direct experimental confirmation of the nonmonotonic dependence of N(E,x) that has previously been predicted theoretically. It is found that at certain values of x the low-temperature heat capacity of the compounds YNi5−xCux increases with decreasing temperature, and the temperature dependence of the electrical resistance has a minimum at T=10 K. Below 10 K the temperature dependence of the resistance obeys a logarithmic law.

The Volleben effect (“paramagnetic” Meissner effect) was revealed for the first time while measuring the temperature dependence of magnetic moments of Dy1–xYxRh4B4 (x = 0.2, 0.3, 0.4, 0.6) in magnetic fields 1–20 Oe. The effect decreases with increasing magnetic field strength, and at fields below 1 Oe a diamagnetic signal appears. The ferromagnetism of Dy atoms supposedly plays an essential role in the appearance of paramagnetic signal at temperatures below the superconducting transition temperature.

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Reentrant spinels Li0.5Fe2.5−xGaxO4 with x=0.9 and 1.2 display peaks on the temperature dependences of heat capacity C at T1=13.4 K (x=0.9) and 14.2 K (x=1.2) respectively, which are typical of a first-order phase transition. This transition is identified with the transformation of the collinear ferrimagnetic structure into a noncollinear structure preceding on the temperature scale the state of ferrimagnetic spin glass existing in the temperature range 0 K⩽T⩽Tf, where transition temperatures Tf are 9 K (x=0.9) and 12 K (x=1.2).

The heat capacity Cm of polycrystalline fullerite C60 doped with nitrogen is measured in the temperature interval 2–13K. The contributions to the heat capacity from translational lattice vibrations (Debye contribution), from orientational vibrations of the C60 molecules (Einstein contribution), and from the motion of the N2 molecules in the octahedral cavities of the C60 lattice are estimated. However, no indications of the first-order phase transformation detected earlier in a dilatometric investigation of the N2–C60 orientational glass are found (beyond the experimental error limits). A possible explanation for this fact is proposed.