Structural and magnetic properties of Gd5Ge4−x P x (x=0.25–0.63)

The Gd5Ge4−x P x (x=0.25–0.63) phases were synthesized and found to adopt the Sm5Ge4-type structure with broken interslab (Ge,P)–(Ge,P) dimers. According to the single crystal X-ray diffraction, substitution of the P for Ge atoms occurs only on the interslab site. Electronic band structure calculations performed with the tight-binding, linear-muffin-tin-orbital method using the atomic sphere approximation confirmed the experimental site preference for the P atoms. Magnetization measurements indicated that all the Gd5Ge4−x P x samples are ferromagnetic with Curie temperatures ranging from 64 to 101K. The ferromagnetic coupling in the samples increases with the P amount, and this is related to an increase in the valence electron concentration. A Griffiths-type phase is observed in the paramagnetic regions for all samples and its stability is discussed.