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Nd3Cu4Sn4, Nd3Ag4Sn4, and Ho3Cu4Sn4 have been studied using 119Sn Mössbauer spectroscopy. Contrary to recent neutron diffraction data, Nd3Cu4Sn4 shows a clear magnetic signal at 1.6 K and has an ordering temperature of 2.0(1) K. Nd3Ag4Sn4 orders at 4.8(1) K, in agreement with neutron diffraction measurements. We observe the ordering of the Ho 2d sublattice in Ho3Cu4Sn4 at 8.2(1) K but we also see some residual magnetic splitting up to 10.5(2) K, which was not previously detected by neutron scattering. [ABSTRACT FROM AUTHOR]

170Yb-Mössbauer spectra have been recorded for h-YbMnO3 over the temperature range of 1.5–40 K. A rapid increase in the Yb 2a-site magnetic hyperfine field and electronic ground state fluctuation time provides microscopic evidence for long-range magnetic order of the Yb 2a-site sublattice below TN2≈5 K. [ABSTRACT FROM AUTHOR]

Nd3Cu4Sn4, Nd3Ag4Sn4, and Ho3Cu4Sn4 have been studied using 119Sn Mössbauer spectroscopy. Contrary to recent neutron diffraction data, Nd3Cu4Sn4 shows a clear magnetic signal at 1.6 K and has an ordering temperature of 2.0(1) K. Nd3Ag4Sn4 orders at 4.8(1) K, in agreement with neutron diffraction measurements. We observe the ordering of the Ho 2d sublattice in Ho3Cu4Sn4 at 8.2(1) K but we also see some residual magnetic splitting up to 10.5(2) K, which was not previously detected by neutron scattering. [ABSTRACT FROM AUTHOR]

170Yb-Mössbauer spectra have been recorded for h-YbMnO3 over the temperature range of 1.5–40 K. A rapid increase in the Yb 2a-site magnetic hyperfine field and electronic ground state fluctuation time provides microscopic evidence for long-range magnetic order of the Yb 2a-site sublattice below TN2≈5 K. [ABSTRACT FROM AUTHOR]

Magnetic, specific heat, and 170Yb-Mössbauer spectroscopy measurements are presented for polycrystalline YbNiAl4. Although the low temperature specific heat data are consistent with the early stages of a magnetic transition, there is no clear evidence for magnetic order down to the lowest experimental temperature of 1.5 K. It is concluded that this is due to an even stronger quenching effect than is predicted by the current crystal field theory. [ABSTRACT FROM AUTHOR]

151Eu and 153Eu Mössbauer spectroscopies have been used to study the magnetism of the Ni2+ moments in Eu2BaNiO5 by way of the exchange-induced Eu3+ moments. These independent and complementary probes indicate that at high temperatures all of the moments in the Haldane quantum spin chains are paramagnetic. On cooling below 25 K, fluctuations of ∼90% of the Ni2+ moments slow down, while the remaining 10% remain paramagnetic (indicating the presence of chain defects). Both 151Eu and 153Eu Mössbauer measurements yield the same Ni2+ moment. Furthermore, below 5 K, the 90% chain component becomes static and ordered, in excellent agreement with the ordering temperature expected from the rare-earth exchange energy. [ABSTRACT FROM AUTHOR]

We have used 197Au Mössbauer spectroscopy along with both neutron and x-ray diffraction to search for site disorder and noncollinear magnetic ordering in PrAu2Si2. There is no evidence of a transferred hyperfine field at the Au site down to 1.7 K allowing us to rule out both collinear antiferromagnetic order and spin-glass ordering of the Pr moments. Full-pattern Rietveld refinement of both neutron and x-ray diffraction data taken over a wide angle range allows us to exclude Au/Si site disorder at the 1% level. We conclude that the Pr moments do not order above 1.7 K in PrAu2Si2, and that the susceptibility peak is likely a dynamic effect. [ABSTRACT FROM AUTHOR]

We have determined the magnetic structure of NdScGe (tetragonal I4/mmm) by high-resolution neutron powder diffraction, ac-susceptibility and magnetometry. The magnetic ordering temperature is 194(2) K and the magnetic structure is characterized by ferromagnetic order of the Nd sublattice, lying in or close to the tetragonal basal plane. The Nd moment at 4 K is 3.2(2) μB and, in contrast to the claims of a recent Perturbed Angular Correlation study, we find no evidence for a lattice softening effect suggested to occur around the Curie temperature. [ABSTRACT FROM AUTHOR]

We have used 197Au Mössbauer spectroscopy along with both neutron and x-ray diffraction to search for site disorder and noncollinear magnetic ordering in PrAu2Si2. There is no evidence of a transferred hyperfine field at the Au site down to 1.7 K allowing us to rule out both collinear antiferromagnetic order and spin-glass ordering of the Pr moments. Full-pattern Rietveld refinement of both neutron and x-ray diffraction data taken over a wide angle range allows us to exclude Au/Si site disorder at the 1% level. We conclude that the Pr moments do not order above 1.7 K in PrAu2Si2, and that the susceptibility peak is likely a dynamic effect. [ABSTRACT FROM AUTHOR]

We review the complementary roles that 119Sn Mössbauer spectroscopy and neutron diffraction are playing in developing a complete description of magnetic ordering in the R3 Cu4Sn4 and R3Ag4Sn4 intermetallic compound series. We show that the two techniques yield consistent pictures of the order, and in many cases both are essential to obtaining a complete description. The recent neutron diffraction work on Sm3Cu4Sn4, Sm3Ag4Sn4 and Gd3Ag4Sn4 is highlighted. [ABSTRACT FROM AUTHOR]

We have previously reported the stability of europium oxalate compared to ammonium europium bis-salen and europium benzoate. We now extend the dicoarboxylic acid chain of the oxalate by introducing additional-CH2-groups in the dicarboxylate ligands by using malonate, succinate, glutarate and adipate. Additionally, we have examined the effect of alterations in the succinate dianion by introducing functional groups such as [C = C]in the case of the maleide and-OH group in the case of the malide. This study is an attempt to further characterize these compounds. Infrared spectra were used to characterize bridging and chelating dicarboxylates while Mössbauer spectroscopy measurements were used to gain better insight into the structure of heterocyclic “cages” containing two Eu3 + ions and two dianions. [ABSTRACT FROM AUTHOR]

Magnetic, specific heat, and 170Yb-Mössbauer spectroscopy measurements are presented for polycrystalline YbNiAl4. Although the low temperature specific heat data are consistent with the early stages of a magnetic transition, there is no clear evidence for magnetic order down to the lowest experimental temperature of 1.5 K. It is concluded that this is due to an even stronger quenching effect than is predicted by the current crystal field theory. [ABSTRACT FROM AUTHOR]

The YbMn(6)Ge(6-x)Sn(x) compounds (0 < x < 6) have been investigated using x-ray diffraction, magnetic measurements, neutron diffraction and (170)Yb Mössbauer spectroscopy. The YbMn(6)Ge(6-x)Sn(x) system comprises three solid solutions: (i) 0 < x ≤ 1.1, (ii) 3.2 ≤ x ≤ 4.6 and (iii) 5.3 ≤ x < 6, all of which crystallize in the hexagonal (P6/mmm) HfFe(6)Ge(6)-type structure. The substitution of Sn for Ge yields changes in the type of magnetic order (antiferromagnetic, helimagnetic, ferromagnetic, conical and ferrimagnetic), in the easy magnetization direction (from easy axis to easy plane) as well as in the valence state of Yb (from trivalent to divalent). The Mn moments order at or above room temperature, while magnetic ordering of the Yb sublattice is observed at temperatures up to 110 K. While Yb is trivalent for x ≤ 1.1 and divalent for x ≥ 5.3, both magnetic and (170)Yb Mössbauer spectroscopy data suggest that there is a gradual reduction in the average ytterbium valence through the intermediate solid solution (3.2 ≤ x ≤ 4.6), and that intermediate valence Yb orders magnetically, a very unusual phenomenon. Analysis of the (170)Yb Mössbauer spectroscopy data suggests that the departure from trivalency starts as early as x = 3.2 and the loss of ytterbium moment is estimated to occur at an average valence of ∼2.5+.