On the magnetovolume effects in YNi3

The thermal expansions of polycrystalline samples of ferromagnetic YNi₃ and paramagnetic YNi₂ have been determined from 4.2 K up to 65 K employing the three-terminal-capacitance method. At low temperatures the expansion of YNi₃ is dominated by a negative magnetic contribution which rapidly vanishes near the Curie temperature. The magnetovolume effects in YNi₃ are discussed within the Stoner-Edwards-Wohlfarth model of very weak itinerant ferromagnetism.