Exploration of magnetic excitation behaviour of actinide compounds with neutron scattering

Buyers, W. J. L.; Holden, T. M.; Jackman, J.A.; Murray, Alan F.; DuPlessis, P. de V.; Vogt, O.

doi:10.1016/0304-8853(83)90228-7

Cited by 32 publications

(6 citation statements)

References 8 publications

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“…The magnetoelastic coupling in USb2 shown in our data is also seen in many other 5felectron systems, including the uranium monochalcogenides, UCu0.95Ge, and UPt2Si2 [8,16,30]. This magnetoelastic transition could indicate a structural phase transition accompanying the magnetic phase transition, similar to the cubic rock salt to rhombohedral distortion in uranium sulfide (US) as it enters the ferromagnetic state [31,32]. Because neutron diffraction measurements at ambient pressure and zero magnetic field do not show such a structural transition in USb2, this may represent a field-stabilized structural transition that is induced through fieldenhanced magnetoelastic coupling.…”

Section: Thermal Expansion and Magnetostrictionsupporting

confidence: 77%

Tricritical point of the f -electron antiferromagnet USb2 driven by high magnetic fields

et al. 2017

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In pulsed magnetic fields up to 65T and at temperatures below the Néel transition, our magnetization and magnetostriction measurements reveal a field-induced metamagnetic-like transition that is suggestive of an antiferromagnetic to ferrimagnetic ordering. Our data also suggests a change in the nature of this metamagnetic-like transition from second-to first-orderlike near a tricritical point at T tc ~145K and H c~5 2T. At high fields for H>H c we found a decreased magnetic moment roughly half of the moment determined by neutron powder diffraction. We propose that the decreased moment and lack of saturation at high fields indicate the presence of a field-induced ferrimagnetic state above the tricritical point of the H-T phase diagram for USb 2 .

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Section: Thermal Expansion and Magnetostrictionsupporting

confidence: 77%

Tricritical point of the f -electron antiferromagnet USb2 driven by high magnetic fields

et al. 2017

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“…2 Below 177 K, US undergoes concomitant magnetic and structural transitions, resulting in a ferromagnetic ground state and a rhombohedral unit cell. [2][3][4][5][6] This rhombohedral unit cell is best described as a small distortion of the cubic rocksalt structure along one of the [111] directions. The ferromagnetic state is characterized by an ordered moment of about 1.55 µ B , manifesting from the sum of a U ion contribution of 1.7 µ B and an antiparallel contribution from the spd conduction electrons of -0.15 µ B .…”

Section: Introductionmentioning

confidence: 99%

Magnetism and structural distortions in uranium sulfide under pressure

et al. 2013

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Uranium sulfide belongs to a class of uranium monochalcogenides that crystallize in the rock-salt structure and exhibit ferromagnetism at low temperature. The magnetism is believed to play a role in the low-temperature rhombohedral distortion, possibly due to its large magnetic anisotropy. We have performed electrical and structural characterization along with density-functional theory calculations as functions of pressure to help understand the interplay between structure and magnetism in US. Theoretical calculations suggest that ferromagnetic order is responsible for the small distortion at ambient pressure and low temperature. Under pressure, the Curie temperature is reduced monotonically until it discontinuously disappears near a pressure-induced deformation of the crystal structure. This high-pressure distortion is identical to the one correlated with the onset of magnetic order, but with a larger change in the cell angle. Calculations imply a reduction in the electronic band energy as the driving force for the pressure-induced structure, but the loss of magnetic order associated with this distortion remains a mystery. The high-pressure electronic phase diagram may shed light on the magneto-structural free energy landscape of US.

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“…The complex electronic structure of uranium leads to a wide variety of unusual and diverse behavior in the uranium salts UX (X = C, N, P, S, As, Se, Sb, Te, Bi), and therefore the materials in this family have been the subject of many past investigations characterizing their magnetic and vibrational properties [1][2][3][4][5][6][7][8][9][10]. The phonon spectra in the UX systems have been comprehensively studied, however there has been renewed interest in more detailed calculations of their vibrational properties as certain members of the family, including UN and UC, are under active consideration for next generation nuclear fuels [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Despite this effort, many unresolved issues remain, including the origin of unusual magnetic excitation spectra in several of the materials [8,9], including antiferromagnetic UN (T N = 53 K [13]) and ferromagnetic US (T c = 180 K [14]). Indeed, our original motivation to study these materials using time-offlight neutron scattering methods was to closely examine the high-energy portion of the magnetic excitation spectra.…”

Section: Introductionmentioning

confidence: 99%

“…The complex electronic structure of uranium leads to a wide variety of unusual and diverse behaviors in the uranium salts UX (X = C, N, P, S, As, Se, Sb, Te, and Bi), and therefore the materials in this family have been the subject of many past investigations characterizing their magnetic and vibrational properties [1][2][3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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Light atom quantum oscillations in UC and US

et al. 2016

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High-energy vibrational scattering in the binary systems UC and US is measured using time-of-flight inelastic neutron scattering. A clear set of well-defined peaks equally separated in energy is observed in UC, corresponding to harmonic oscillations of the light C atoms in a cage of heavy U atoms. The scattering is much weaker in US and only a few oscillator peaks are visible. We show how the difference between the materials can be understood by considering the neutron scattering lengths and masses of the lighter atoms. Monte Carlo ray tracing is used to simulate the scattering, with near quantitative agreement with the data in UC, and some differences with US. The possibility of observing anharmonicity and anisotropy in the potentials of the light atoms is investigated in UC. Overall, the observed data is well accounted for by considering each light atom as a single atom isotropic quantum harmonic oscillator.

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Exploration of magnetic excitation behaviour of actinide compounds with neutron scattering

Cited by 32 publications

References 8 publications

Tricritical point of the f -electron antiferromagnet USb2 driven by high magnetic fields

Tricritical point of the f -electron antiferromagnet USb2 driven by high magnetic fields

Magnetism and structural distortions in uranium sulfide under pressure

Light atom quantum oscillations in UC and US

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