Neutron diffraction study of UCu4.5Al7.5, (U, Th)Fe4Al8 and UFe6Al6 compounds

Ptasiewicz-Bak, B.; Baran, A.; Suski, W.; Leciejewicz, J.

doi:10.1016/0304-8853(88)90449-0

Cited by 38 publications

(14 citation statements)

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“…4. The UFe Al presents a ferromagnetic behaviour below 300(1) K. This transition is confirmed by AC susceptibility measurements that show a peak at 295(2) K. For higher temperatures a Curie-Weiss law behaviour is followed, with "304(2) K. This transition temperature is significantly lower than those previously reported for UFe Al from powder magnetisation and Mo¨ssbauer measurements: 355 K [11], 334 K ( Table 1 in Ref. [24]), 350 K [10].…”

Section: Resultssupporting

confidence: 60%

“…Previous measurements on UFe Al powder samples indicate a ferromagnetic character [6,10]. Powder neutron diffraction results suggest that the iron moments in UFe Al and UFe Al are ordered in a configuration perpendicular to the c axis [10,11]. However, the study of magnetic and other physical properties in these samples was limited due to the lack of single crystals.…”

Section: Introductionmentioning

confidence: 97%

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Crystallographic and magnetic properties of UFe5.8Al6.2 single crystals

Gonçalves¹,

Estrela

Waerenborgh³

et al. 1998

Journal of Magnetism and Magnetic Materials

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Single crystals of UFe Al were characterised by X-ray and neutron diffraction, Fe Mo¨ssbauer spectroscopy and magnetisation. The structure refinement by X-ray and neutron diffraction shows a ThMn -type structure, the Fe atoms fully occupying the 8f and partially occupying the 8j positions. Mo¨ssbauer spectra confirm these occupations and further indicate a magnetic ordering below 293 K. Magnetisation measurements show a ferromagnetic behaviour below 300 K, with a and b as easy directions and a spontaneous magnetisation of 10.4 /f.u. at 5 K, due to the Fe occupation of 8j position. These single crystal results significantly differ from those previously obtained in UFe Al polycrystalline samples obtained by melting and annealing.

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Section: Resultssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 97%

Crystallographic and magnetic properties of UFe5.8Al6.2 single crystals

Gonçalves¹,

Estrela

Waerenborgh³

et al. 1998

Journal of Magnetism and Magnetic Materials

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“…The magnetic properties of UFe 4 Al 8 were studied earlier 5-10 on polycrystalline samples, by ac susceptibility, 5,8 magnetization, 5,8-10 neutron diffraction, [6][7][8]10 and 57 Fe Mössbauer spectroscopy. 8,10 The results were quite different and some of them turned out to be incorrect.…”

Section: Introductionmentioning

confidence: 99%

Magnetic phase diagram of the semiordered alloysUFexAl12−x

Kuznietz¹,

Gonçalves²,

Waerenborgh³

et al. 1999

Phys. Rev. B

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Single crystals of the ternary semiordered alloys UFe x Al 12Ϫx with xϭ3. 8, 4.0, 4.2, 4.5, 4.7, 5.0, 5.5, and 5.8, were prepared, and found to crystallize in the tetragonal ThMn 12 -type structure ͑space group I4/mmm͒. Studies of monocrystalline and polycrystalline samples of these materials, by ac susceptibility, magnetization, and 57 Fe Mössbauer spectroscopy, show two magnetic transitions in the range of 4.0ϽxՇ4.7, where only a single transition has been previously reported for polycrystalline materials. These measurements yield the magnetic phase diagram of this system, extending the magnetic structures of single crystal UFe 4 Al 8 , determined by ͑unpolarized and polarized͒ neutron diffraction, of polycrystalline UFe 5 Al 7 , determined elsewhere by neutron diffraction, and of single crystal UFe 5.8 Al 6.2 , determined by magnetization. The four magnetic regions, identified in the magnetic phase diagram, and their proposed magnetic structures, are discussed.

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“…This compound shows a ferromagneticlike behavior below 150 K. 3 Extensive studies by means of magnetization measurements, Mössbauer spectroscopy, and neutron diffraction techniques on powder samples led to contradictory interpretations of the magnetic configuration of the Fe and U atoms. [4][5][6][7][8][9] These conflicting results may in part be explained by slight deviations from ideal stoichiometry as well as by a certain freedom of choice of site (8 f -8 j) by the Fe atom. 9 In the UFe x Al 12Ϫx intermetallics, namely, in the case of UFe 5.8 Al 6.2 , the resulting structural disorder was found to be strongly dependent on the synthesis conditions.…”

Section: Introductionmentioning

confidence: 99%

Anomalous magnetization cycle ofUFe4Al8single crystals: A Mössbauer effect study

et al. 1999

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An 57 Fe Mössbauer spectroscopy study was performed on an UFe 4 Al 8 single crystal, in an external magnetic field B ext , subtending an angle of 11°at the b axis. It shows that, even in low fields, the configuration of the Fe magnetic moments, Fe , is consistent with the canted antiferromagnetic order of Fe , established by single-crystal neutron diffraction in a field of 4.6 T. The canting of Fe is always observed towards the direction of the U magnetic moments U , clearly showing that it is induced by U rather than by B ext . At a certain value of B ext during the magnetic domain rotation, the direction of Fe is found to be temporarily frozen approximately along the direction of B ext . This confirms previous magnetization and magnetoresistance data, which show that for the same values of B ext , U is blocked perpendicularly to B ext . Furthermore, the present study reveals that this blocking is a metastable state with a relaxation time of a few hours, at 4.2 K.

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Neutron diffraction study of UCu4.5Al7.5, (U, Th)Fe4Al8 and UFe6Al6 compounds

Cited by 38 publications

References 0 publications

Crystallographic and magnetic properties of UFe5.8Al6.2 single crystals

Crystallographic and magnetic properties of UFe5.8Al6.2 single crystals

Magnetic phase diagram of the semiordered alloysUFexAl12−x

Anomalous magnetization cycle ofUFe4Al8single crystals: A Mössbauer effect study

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