Valence change of Sm ion in Eu1−xSmxSe

Crystallographic and magnetic investigations of Eu 1− x Sm x Se mixed crystals have been made. The x dependence of the lattice constant shows a deviation from the usual Vegard law and suggests an intermediate valence of Sm ions in EuSe host, which is about 2.3 for x ⩽ 0.2. The substitutive Sm ion influences magnetic properties of EuSe as a non-magnetic ion with smaller ionic radius than the Eu 2+ ion.