Strong magnetic coupling in the hexagonal R5Pb3 compounds (R=Gd–Tm)

Abstract

We have synthesized R 5 Pb 3 (R = Gd-Tm) compounds in polycrystalline form and performed structural analysis, magnetization, and neutron scattering measurements. For all R 5 Pb 3 reported here the Weiss temperatures θ W are several times smaller than the ordering temperatures T ORD , while the latter are remarkably high (T ORD up to 275 K for R = Gd) compared to other known R-M binaries (M = Si, Ge, Sn and Sb). The magnetic order changes from ferromagnetic in R = Gd, Tb to antiferromagnetic in R = Dy-Tm. Below T ORD , the magnetization measurements together with neutron powder diffraction show complex magnetic behavior and reveal the existence of up to three additional phase transitions.We believe this to be a result of crystal electric field effects responsible for high magnetocrystalline anisotropy. The R 5 Pb 3 magnetic unit cells for R = Tb-Tm can be described with incommensurate magnetic wave vectors with spin modulation either along the c axis in R = Tb, Er and Tm or within the ab-plane in R = Dy and Ho.Keywords: rare earth led binary systems, incommensurate magnetic structure, crystal field effects. I. INTRODUCTIONThe discovery of intermetallic compounds with the chemical formula R 5 M 3 (R = rare earth, M = Si, Ge, Sn, Sb and Bi) attracted attention in condensed matter physics because of their rich structural and physical properties. R 5 Si 3 compounds (R = La-Nd) crystallize in the Cr 5 B 3 -type tetragonal structure 1, 2 with space group (SG) I 4 /mcm, while the R = Gd-Lu, Y, members of this series crystallize in the Mn 5 Si 3 -type hexagonal structure with SG P6 3 /mcm. 3, 4 All R 5 Bi 3 compounds crystallize in the orthorhombic Y 5 Bi 3 -type structure with SG Pnma. 2, 5, 6 R 5 M 3 (where R = La-Nd, Gd-Lu and M = Ge, Sn, Sb, Pb) adopt a hexagonal P6 3 /mcm structure, in which the R atoms (R 1 , R 2 ) occupy two inequivalent crystallographic sites, with 2(3) R 1 (R 2 )/f.u. in the 4d(6g) positions. Thus one

Anisotropic magnetic property of single crystals $R$V$_6$Sn$_6$ ($R$ = Y, Gd - Tm, Lu)

“…[35,36] For the compounds with heavy rare-earths, T N should decreases monotonically as R traverses from Gd to Yb. The ordering temperatures in many rare-earth-based intermetallic compounds follow this scaling [37][38][39][40]. However, when there are strong CEF effects, a deviation from the linear de Gennes scaling has been observed for R = Tb -Yb.…”

Competing magnetic interactions and magnetocaloric effect in Ho5Sn3

“…Among the binary and pseudo-binary heavy RE compounds and alloys, Gd 5 Ge 4 based compositions with 5:4 stoichiometry are the most widely studied materials due to their exotic ground state, metastability, phase coexistence, magneto-structural instability and above all giant MCE [20]. In contrast, the RE 5 X 3 (X is a non-magnetic element) compositions are much less studied [21][22][23][24][25][26][27][28][29][30][31][32]. This paper focuses on the magnetic and magnetocaloric properties of a Ho-based REI compound Ho 5 Sn 3 .…”

Competing magnetic interactions and magnetocaloric effect in Ho$_5$Sn$_3$

“…Among the binary and pseudo-binary heavy RE compounds and alloys, Gd 5 Ge 4 based compositions with 5:4 stoichiometry are the most widely studied due to their exotic ground state, metastability, phase coexistence, magneto-structural instability and above all giant MCE 17 . In contrast, the RE 5 X 3 (X is a non-magnetic element) compositions are much less studied [18][19][20][21][22][23][24][25][26][27][28][29] . This paper focuses on the magnetic and magnetocaloric properties of a Ho-based REI compound Ho 5 Sn 3 .…”