Gadolinium spin dilution in the ferromagnetic solid solutions Gd2–xYxCu2Mg.

Samples of the solid solution Gd2–xYxCu2Mg (in steps of x = 0.2) were synthesized from the elements in sealed tantalum ampoules in a high-frequency furnace. The polycrystalline samples were characterized by X-ray powder diffraction. The structure of Gd0.988(6)Y1.012(6)Cu2Mg was refined from single-crystal X-ray diffractometer data: Mo2B2Fe type, P4/mbm, a = 762.83(4), c = 375.48(2) pm, wR2 = 0.0277, 285 F2 values and 13 variables. Single-crystal data gave no hint for Gd/Y ordering. All samples behave like Curie-Weiss paramagnets with stable trivalent gadolinium and ferromagnetic ordering at low temperature. Within the solid solution the Curie temperature drops almost linearly from TC = 113.5(1) K for Gd2Cu2Mg to 9.3(1) K for Gd0.2Y1.8Cu2Mg, allowing a precise adjustment of the magnetic ordering temperature through gadolinium spin dilution. [ABSTRACT FROM AUTHOR]