Low-temperature heat-capacity studies ofR2Ni3Si5

Abstract

We report here our low temperature (2Ϫ30 K) heat capacity, C p measurements of R 2 Ni 3 Si 5 (R ϭPr, Nd, Sm, Gd-Ho). Large peaks in heat capacity data at magnetic transition temperatures (T N ) confirm the bulk nature of magnetic order in these compounds. In Nd 2 Ni 3 Si 5 , Gd 2 Ni 3 Si 5 , and Dy 2 Ni 3 Si 5 , magnetization studies indicated only one magnetic transition, whereas, heat-capacity data show two transitions. T N of the heavier rare-earth member, Tb 2 Ni 3 Si 5 , showing significant deviation from de Gennes scaling is notable. Magnetic entropy, ⌬S, estimated from heat-capacity data suggest that the magnetic ground state is a doublet in R 2 Ni 3 Si 5 (RϭPr, Nd, Sm, Dy, Ho) and a quartet in Tb 2 Ni 3 Si 5 . In all the cases, ⌬S, at T N is slightly less than that expected due to the suggested states, which we attribute to the occurrence of precursor effects of magnetic order above T N . Except for Gd 2 Ni 3 Si 5 , ⌬S of the compounds does not reach the saturation limit of R ln(2Jϩ1) even at 30 K, indicating the presence of crystalline electric field ͑CEF͒ effects. A hump in C p is observed below T N in Gd 2 Ni 3 Si 5 which is interpreted in terms of a possible amplitude-modulated magnetic spin structure. ͓S0163-1829͑99͒12605-5͔

Double-phase transition and giant positive magnetoresistance in the quasi-skutterudite Gd3Ir4Sn13

“…However, magnetoresistance anomalies in Gd-alloys have been studied in detail and documented well. [34][35][36][37][38][39] It is interesting to note that the temperature dependence of electrical resistivity of Gd-alloys like GdCu 2 Si 2 and GdNi 2 Si 2 resemble that of Gd 3 Ir 4 Sn 13 . 34 The MR is observed to be positive for GdCu 2 Si 2 above the Néel temperature.…”

Electronic structure of superconducting Lu2Ni3Si5 and its reference compound Y2Ni3Si5 by ab initio calculations

“…La3Ni4Si4 [6,7]. It is interesting that most of the R2Ni3Si5-family members exhibit antiferromagnetic phase transitions at temperatures TN ≤ 30 K and the magnetic moments, originating only from the rare-earth atoms because the nickel atoms remain non-magnetically ordered (NMO) [8][9][10][11][12][13][14]. In antiferromagnetically ordered (Pr;Dy;Ho)2Ni3Si5 systems, an existence of also short-range ferromagnetic (FM) correlations has been postulated, based on observations of an anomalous behavior of magnetoresistivity [15].…”

Antiferromagnetism in the Kondo lattice compoundCe2Pd3Si5Huo1, Sakurai2, Kuwai3 et al. 2002Phys. Rev. B230100View full textAdd to dashboardCite

“…5. Although a hump of specific heat below T N is often observed in Gd-based compounds, 22,23 it is unusual in Ce-based compounds. Blanco et al 28 showed that C mag of an amplitude-modulated moment Gd-based system below T N shows a hump with a decrease in the peak height at T N .…”