Magnetoresistance behavior of ternary rare-earth compounds near the Néel temperature

Abstract

The results of the magnetoresistance (Δρ/ρ) measurements of the compounds PrCu₂Si₂, PrCu_1.7Ni_0.3Si₂, PrCu_0.5Ni_1.5Si₂, GdNi₂Si₂, GdCu_0.4Ni_1.6Si₂, and PrCu₂Ge₂ in the vicinity of the Néel temperature (T_N) are presented. The magnetoresistance in these samples below T_N is found to exhibit a variety of behaviors depending upon the magnetic moment of the rare-earth ions and the position of the Fermi level with respect to the antiferromagnetic energy gap. The results also indicate the existence of short-range magnetic-order effects well above T_N and spin fluctuations (presumably due to Ni) in GdNi₂Si₂. Features characterizing the existence of a metamagnetic transition below T_N in the PrCu₂Ge₂ around 15 kOe are also observed. The observations are of relevance to the understanding of magnetoresistance behavior in Ce and U materials.