Europium spin dilution in the ferromagnetic solid solution Eu4–x Ca x PdMg

Abstract The intermetallic compounds Eu 4 PdMg and Ca 4 PdMg form a complete solid solution Eu 4– x Ca x PdMg. Further phase analytical studies showed that Eu 4 PdMg does not allow substitution with strontium. The polycrystalline Eu 4– x Ca x PdMg samples were characterized by powder X-ray diffraction. The structure of Eu 2.233(6) Ca 1.767 PdMg was refined from single crystal X-ray diffractometer data: Gd 4 RhIn type, F 4 ‾ 3 m , a = 1,475.42(10) pm, w R 2 = 0.0476, 674 F 2 values, 23 variables. Temperature dependent magnetic susceptibility measurements show a drastic decrease of the Curie temperature with increasing calcium substitution. 151 Eu Mössbauer spectra of Eu 4 PdMg and Eu 2 Ca 2 PdMg confirm the divalent ground state of europium.