Anomalous Behavior in Electrical Transport Properties in Single-Crystal Gd $_{5}$ Si $_{1.8}$ Ge

Gd₅(Si_xGe_1-x)₄ exhibits anomalous behavior in resistivity measurement close to its first-order phase transition temperature. In this paper, we present a series of resistivity as a function of temperature measurements indicating an irreversible change in the resistivity. The resistivity of the sample increased every time the sample was passed through first-order phase transition for both single-crystal Gd₅Si_1.8Ge_2.2(x=0.45) and polycrystalline Gd₅ Si_2.09 Ge_1.91(x=0.522). Magnetic hysteresis loops were also plotted for the single-crystal Gd₅ Si_1.8 Ge_2.2 at 220 K. The hysteresis loops were measured several times at 220 K, cycling the temperature between 220 and 300 K between each measurement. The coercivity of the sample increased irreversibly when the sample was passed through the first-order phase transition. The increase in the coercivity was 20 Oe for the fourth and fifth thermal cycles and then it remained constant up to 15 thermal cycles.