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The effect of the volume expansion on the total linear magnetostriction of Fe85Ga15, Fe80Ga20, and Fe71Ga29 mold-cast bulk alloys was investigated by measuring the change in length with applied field longitudinal and perpendicular to the temperature gradient during solidification. In the magnetically saturated state, due to the contribution of the volume expansion, the saturation magnetostriction for all three alloys was about 66 % of the total linear magnetostriction. The magnetostriction is strongly dependent on the direction of the temperature gradient, being larger in this direction. The substitution of Fe by Ga atoms increases the lattice constant and causes a change to the A2 crystal structure, which was confirmed by Mössbauer spectroscopy. The thermal-expansion coefficient increases with Ga content at temperatures between 4.2 and 150K.

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To elucidate the discrepancies in low-temperature data reported on the quantum critical heavy fermion compound Ce 3 Pd 20 Si 6 and reveal the compound's intrinsic properties, single crystals of varying stoichiometry were grown by various techniques-from the melt and from high-temperature solutions using fluxes of various compositions. The resulting stoichiometry of the crystals as well as their physical properties show sizable dependence on the different growth techniques. The Ce content ⌬Ce varies by more than 3 at. % among all grown single crystals. We have revealed a systematic dependence of the residual resistance ratio, the lattice parameter, the ͑lower͒ phase-transition temperature T L , and the maximum in the temperature dependent electrical resistivity T max with ⌬Ce. This clarifies the sizable variation in the values of T L reported in the literature. We discuss the physical origin of the observed composition-property relationship in terms of a Kondo lattice picture. We predict that a modest pressure can suppress T L to zero and thus induce a quantum critical point.

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