title: Magnetic and electrical transport anomalies of RMAs(2) (R = Pr and Sm, M = Ag and Au).
abstract: The results of magnetization, heat capacity and electrical resistivity (ρ) studies of the compounds RMAs(2) (R = Pr and Sm; M = Ag, Au), crystallizing in an HfCuSi(2)-derived structure, are reported. PrAgAs(2) orders antiferromagnetically at T(N) = 5 K. The Au analog, however, does not exhibit long range magnetic order down to 1.8 K. We infer that this is due to subtle differences in their crystallographic features, particularly noting that both the Sm compounds with identical crystal structures as that of the former order magnetically nearly at the same temperature (about 17 K). It appears that, in PrAgAs(2), SmAgAs(2) and SmAuAs(2), there is an additional magnetic transition at a lower temperature, as though the similarity in the crystal structure results in similarities in magnetism as well. The ρ for PrAgAs(2) and PrAuAs(2) exhibits a negative temperature coefficient in some temperature range in the paramagnetic state. SmAuAs(2) exhibits a magnetic Brillouin-zone gap effect in ρ at T(N), while SmAgAs(2) shows a well-defined broad minimum well above T(N) around 45 K. Thus, these compounds reveal interesting magnetic and transport properties.
authors.affiliation: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India.
authors.forename: K
authors.initials: K
authors.lastname: Mukherjee
authors.forename: E V
authors.initials: EV
authors.lastname: Sampathkumaran
authors.forename: D
authors.initials: D
authors.lastname: Rutzinger
authors.forename: Th
authors.initials: T
authors.lastname: Doert
authors.forename: M
authors.initials: M
authors.lastname: Ruck