R2Co3-xSix (R = Pr, Nd, Sm, Gd) and R2Ni3-xSix (R = Gd-Er), new series of La2Ni3-type phases

Abstract

In this study, we have expanded our previous work on the Gd2(Co3-xSix) system to form the family of R2(T3-xSix) compounds with a wide range of the rare earth metals (Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er) by variation of the composition and, where necessary, the transition element (Co and Ni). We report the crystallographic and the magnetic properties of this La2Ni3-type series. The R2Co3-xSix compounds with R= Pr, Nd, Sm and Gd, undergo ferro-or ferrimagnetic transitions at TC ranging from 64 K (Nd) to 338 K (Gd) and the R2Ni3-xSix phases with R = Gd-Er display ferromagnetic order below TC from 96 K (Gd) to 7 K (Er).

Robust antiferromagnetism in Y$_2$Co$_3$

“…Among all of these La 2 Ni 3 -type R 2 Co 3−x Si x (0 ≤ x < 0.5) compounds, only La 2 Co 3 and Y 2 Co 3 have an antiferromagnetic ordering. Other compounds in this family show ferrimagnetic orderings with Curie temperatures varying from 64 K (Pr) to 388 K (Gd) [11]. Interesting magnetic properties due to their complex magnetic structures were observed in this family, including strong magnetocaloric effect (Gd 2 Co 3−x Si x ) and metamagnetic transition (Pr 2 Co 2.8 Si 0.2 ) [11].…”

“…The space group is Cmce (No. 64), La 2 Ni 3 -type structure, with cell parameters a = 5.3302 (11) Å, b = 9.5067 (19) Å and c = 7.1127( 14) Å. Table I gives the atomic position (x, y, z), equivalent parameters and occupancy for Y 2 Co 3 .…”

“…earth elements (Pr, Sm, Gd,) can form such a structure, albeit with Si substitutions [10][11][12]. Among all of these La 2 Ni 3 -type R 2 Co 3−x Si x (0 ≤ x < 0.5) compounds, only La 2 Co 3 and Y 2 Co 3 have an antiferromagnetic ordering.…”

“…Other compounds in this family show ferrimagnetic orderings with Curie temperatures varying from 64 K (Pr) to 388 K (Gd) [11]. Interesting magnetic properties due to their complex magnetic structures were observed in this family, including strong magnetocaloric effect (Gd 2 Co 3−x Si x ) and metamagnetic transition (Pr 2 Co 2.8 Si 0.2 ) [11]. However, the magnetic structures of these R 2 Co 3−x Si x compounds are complicated by the presence of two magnetic elements: rare-earth element and Co.…”

Two polymorphs of a new intermetallic Ce2Rh2Ga – crystal structure and physical properties

“…Two of these are monoclinic ones: HT-Pr2Co2Al or Ca2Ir2Si (C2/c) -stacking variant of the W2B2Co [16,17] -and LT-Nd2Cu2Cd (C2/c, own structure type) -superstructure of Mn2B2Al [18]; the other three structures are orthorhombic: La2Ni3 (Cmce) [19], o-La2Ni2In (Pbam) [20], and Ca2Pd2Ge (Fdd2) [21]. Only a few representatives of these types are reported to date [22][23][24][25][26].…”