Magnetization and specific heat study of metamagnetism in Lu_2Fe_(17)-based intermetallic compounds

摘要

The effects of substitutions of Ru for Fe and Ce for Lu on magnetic and thermal properties of Lu_2Fe_(17) are studied by means of magnetization and specific heat measurements on single-crystalline samples of Lu_2Fe_(17-x)Ru_x (x = 0, 0.5 and 1) and (Lu_(0.8)Ce_(0.2))_2Fe_(17). It is shown that both substitutions lead to the suppression of the low-temperature ferromagnetic (F) phase present in the initial Lu_2Fe_(17) compound, resulting in stabilization of the antiferromagnetism in the whole range of magnetic order. An increase of the Sommerfeld coefficient γ is found for both substitution cases. The results are discussed taking into account the interatomic distance variation and the change of the electronic structure upon substitution. Thermal properties of (Lu_(0.8)Ce_(0.2))_2Fe_(17) and Lu_2Fe_(16.5)Ru_(0.5) are also studied across the metamagnetic transition restoring the F coupling.