Magnetism of rare-earth disilicides

Abstract

Magnetic and electrical properties of polycrystalHne RSi z compounds, where R = La~ Yb and Y, have been investigated at temperatures ranging from 1.8 K to room temperature using superconducting quantum-interference device (SQUID) magnetometry, ac susceptibility, resistivity, and magnetoresistance measurements. Our data indicate that while PrSi 2 , ErSi z , and TmSi z order ferromagnetically at 11,2.8, and below 1.8 K, respectively, other RSi z compounds with R = Nd, Eu, Gd, Tb, Dy, and Ho order antiferromagneticaUy with TN<39 K. All compounds show Curie-Weiss behavior in the paramagnetic region and the effective moments are found to be close to the free~ion values, gJ [J(J + 1)] 1/2 • Another interesting feature is the observation of second transitions in the cases of Pr, Nd, Eu, Gd, Tb, and Dy compounds. SmSi 2 , CeSi 2 , and YbSi 2 do not show any magnetic order down to 1.8 K. In the

Structural chemistry, magnetism and electrical properties of binary Gd silicides and Ho3Si4

“…7): both χ and χ dc pass identical maxima at T N = 26 K. The negative θ p and the temperature independent χ is a good indication that this compound undergoes an antiferromagnetic transition at this temperature, too. This observation is in accord with literature [38][39][40]. Upon lowering the temperature, an additional but broad maximum (χ (T)) and wide shoulder (χ dc (T)) is observed.…”

“…The temperature independent contribution χ o was found in the order of 4 × 10 −10 m 3 /mol. The magnetic moment also agrees with the literature data [38][39][40]. The ac (B = 10 mT) and the dc (B = 0.1 T) susceptibilities lead to the following results (inset Fig.…”

“…However, we note a pronounced field dependence of χ and χ dc (different heights of the maximum and shoulder) as well as a temperature dependence of χ . Hence, it can be concluded that this compound also undergoes a ferromagnetic-like transition at a Curie temperature T C = 14 K. This second transition was not previously observed [38], but some authors report a second magnetic transition at T = 39 K [39,40], which was not encountered in this study.…”

Valence instability of europium in EuCo2Si2

“…In the latter system, no data on intermediate phases were found so far [18]. Magnetic behaviour is known and does not correspond to our data for Co [19], Eu [20], Co 1−x Si x [21], ␣-Co 2 Si [22], CoSi [23], CoSi 2 [24], EuSi [25], Eu 3 Si 4 [26] and EuSi 2 [27]. Co 3 Si and ␤-Co 2 Si are stable only at high temperatures [16].…”

The electronic structure and magnetism of GdSi2 by first-principles study

“…For all systems, antiferromagnetic (AFM) states are found to be energetically more stable, compared to the corresponding ferromagnetic (FM) states by quite small energy differences of 38, 27, and 24 meV/ formula for the hexagonal, tetragonal, and orthorhombic crystal structures, respectively, as shown in Table 1. This result is consistent with an experiment [6] which observed AFM with T N ¼ 39 K.…”