Anomalous Behavior in Electrical Transport Properties in Single-Crystal Gd$_{5}$Si$_{1.8}$Ge$_{2.2}$ and Polycrystalline Gd $_{5}$Si $_{2.09}$Ge $_{1.91}$

Gd
₅
(Si
_x
Ge
_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 Gd
₅
Si
_1.8
Ge
_2.2
(x=0.45) and polycrystalline Gd
₅
Si
_2.09
Ge
_1.91
(x=0.522). Magnetic hysteresis loops were also plotted for the single-crystal Gd
₅
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.