Kristallstruktur und magnetisches Verhalten des metallischen Holmiums

The crystal structures and accurate lattice constants of scandium, yttrium and the rare earth metals are given, and the values of their calculated mole-atomic volumes, densities, axial ratios and metallic radii are graphically compared. Expected variations due to the 'lanthanide contraction' and structure differences are noted, and additional irregularities in the axial ratio and metallic radii plots are indicated.

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“…Work was performed in the Ames Laboratory of the U.S. Atomic Energy Commission. ~f Bommer, 1939a;Meisel, 1939. ++ Bommer, 1939aQuill, 1932a, b.…”

Section: Sample Preparation and Equipmentmentioning

confidence: 99%

The crystal structures and lattice parameters of high-purity scandium, yttrium and the rare earth metals

Spedding¹,

Daane²,

Herrmann³

1956

Acta Cryst

256

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“…Europium has been characterized by several workers (3,13) as divalent in the metallic state. This is again borne out by the isomer shift of the metal, which is clearly much closer to that of the covalent divalent compounds than that of the covalent trivalent compounds.…”

Section: "Valence" In the Metallic Statementioning

confidence: 99%

Mössbauer Spectroscopy of the Rare Earths

Clifford¹

1967

Advances in Chemistry

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Applications of Mössbauer spectroscopy to strictly chemical problems of the lanthanides have been few.Nevertheless, some interesting chemical relationships can be derived from physical work-e.g., that of Hüfner on 151 Eu. The relative degrees of ionicity of various europium compounds implied agrees with Pearson's designation of lanthanide ions as "hard acids." Likewise, data from the recent work of Nowik on dysprosium intermetallics suggests "valences" of the metals in the alloys-a topic of considerable interest to chemists. Almost no chemical information on the lanthanides has been derived from quadrupole splittings. However, we have recently investigated compounds of europium in which the bonding or crystal environment apparently causes quadrupole splitting. Asymmetric broadening attributable to quadrupole splitting has been observed in Eu 2 O 3 , and evidence for quadrupole splitting has been found in other compounds.As of September 1966, nuclear gamma ray resonance (the Môssbauer effect) has been observed in at least nine of the rare earth elements:160Dy? 161Dy? 166Erj 151Eu? 153EU) 155Gd) 156^ 237Np> 14ipr? lS9Tbj 169^ 170 Yb, and 171 Yb. In some of these cases the energy of the Môssbauer transition is so high (e.g., 141 Pr, 145 k.e.v.) or the line width so broad (e.g., 159 Tb, t% = 0.13 nsec.) that it severely limits any usefulness for studying chemical problems. In the case of alpha-emitting elements, radiation damage to the crystal matrix may becloud the chemistry being investigated. In several more cases, as the nuclear properties of the isotopes become better known, more usable nuclides may become evident.In most of the cases cited above the aim of the study has been to investi gate nuclear or physical effects. In particular, considerable attention has been paid to the magnetic hyperfine splitting. Although there are no Môssbauer studies on the rare earths of avowedly chemical nature in the 113

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“…In 1937 (4) and 1939 (5), Klernin and Bommer studied the paramagnetic sus ceptibility of gadolinium, terbium, dysprosium, holmium, and erbium and found that the susceptibility was large in all cases and that they all had paramagnetic Curie temperatures between 0°K and room temperature.…”

mentioning

confidence: 99%

“…so that the saturation magnetization, according to Equation 1-1 is given by M = NgJug . (1)(2)(3)(4)(5)(6)(7)(8) Here, the effective number of Bohr magnetons is M-eff ~ gJ • (1--9) This corresponds to the situation where the spins of all the ions are parallel and in this regard is equivalent to the ferromagnetic case.…”

mentioning

confidence: 99%

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The magnetic properties of single crystals of erbium and some yttrium-erbium and lutetium-erbium alloys between 1.2 and 300°K

Gray

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Carefully analyzed splierical cinclc crystal riamplex wore prepared oL' orbiiiiu and of alloyy whose approximate compositions were: , Y^oEr,;^. Y?Er-^ , LUo-jEr^^, Lu^oEr^o, and. Ma^pietie measureraerits were made on each ol' these samples along the tt'iroc principle crystallographic axes in the range 1.2 to gOO^K and applied fields up to K-Oe. For pure erhiim, the saturation moment along the c-axis was found to be 270.O ±2.0 emu/g. by fitting the data to a plot and extrapolating to 0°K. This is to be compared with a theoretical value of 3OO.5 emu/g. The discrepancy between experiment and theory is apparently the result of a ferromagnetic spiral arrangement of spins where the spins are cocked at an angle to the c-axis rather than being aligned parallel to it. Curie and N^el temperatures were found at l8.2 ±0.5 and 86.5 ±0.5°K respectively. Peaks in the c-axis moment vs. temperature curves were also observed which extrapolated to zero-field temperatures of 28.0 ±0.5 and 50.5 ±0.5°K. The latter corresponds to the transition from one antiferromagnetic structure to another while the significance of the former is unknown. Peaks occurred in both the a-and b-axis moment vs. temperature curves below about 18.5 K-Oe. Below about 10 X-Oe., the temperature of the peaks was field independent and occurred at about l8.2°K. In both the a-and b-axis moment vs. field curves, there were discontinuous increases in moment at about 18.5 K-Oeo near 4.2°K. These apparently correspond to a sudden transition to a nearly parallel alignment of spins at an angle of about 23° to the c-axis. Some very small basal-plane anisotropy was observed below 40°K. At 4.2°X, the b-axis moment was about 2% larger at .high V rie Id:: " None or I,lie alloyt; ;;i,uii.ic:d wore i'crromfinotic in zrjro l'i'tld. 'I'ha l.timprrattircr, of thn alloyri ware proportional to thr: %/% jkw. t oT th'.; _2 avcra}:c do Gennos factor, = AG''\ The constant, A, warj found to bo '19.0 for tlio yttriiun-crbium alloys and 53*5 for the lutetium-erbium alloys. An anomalouiî peak was observed in the c-axis moment vs. temperature curves for two alloys, LuggEr^g and YgoErgg. In both alloys, the peak vfas not observed at fields less than about 6 K-Oe. However, by extrapolating to zero field, the temperatures of the peaks were determined to be 27-5 ±1.0 and 17•5 ±1.0°K respectively for the two alloys. In addition to these • anomalies, a peak was observed at 29.0 ±0.5°K for a polycrystalline YggEryg alloy by a zero-field mutual-induetance bridge technique. These peaks are evidently due to a transition between two different magnetic structures, but whether they correspond to the structure change observed by Child _et in yttrium-erbium alloys is not known. Peaks occurred in both the a-and b-axis moment vs. temperature curves for the YssEr^g, LugsEr^s, YgoErgo, and LUgoErso alloys at l6.4, I6.I, 12.5, and about 9.0°K respectively. These peaks are apparently related to the l8.0°K basal-plane peak in pure erbium. This peak corresponds to the ferromagnetic-antiferromagnetic transition in p...

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Kristallstruktur und magnetisches Verhalten des metallischen Holmiums

Abstract: 1. Holmium kristallisiert in hexagonal dichter Packung mit den Achsen a = 3,557 und c = 5,620.

Cited by 17 publications

References 7 publications

The crystal structures and lattice parameters of high-purity scandium, yttrium and the rare earth metals

The crystal structures and lattice parameters of high-purity scandium, yttrium and the rare earth metals

Mössbauer Spectroscopy of the Rare Earths

The magnetic properties of single crystals of erbium and some yttrium-erbium and lutetium-erbium alloys between 1.2 and 300°K

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