Uniaxial magnetic anisotropy in Fe-rich 2:17 compounds with <i>sp</i> substitutions

Dunlap, R. A.; Wang, Z.; Földeáki, M.

doi:10.1063/1.358187

Cited by 11 publications

(7 citation statements)

References 12 publications

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“…and 6.5 atoms/f.u., respectively. 46,49 In contrast with the nonmagnetic rareearth compounds, where there is supremacy of K 1 , in U 2 Fe 12 Al 5 K 2 clearly dominates the anisotropy energy at all temperatures, pointing to an important influence of the uranium magnetic sublattice.…”

Section: H Mmentioning

confidence: 98%

Structural, Magnetic, and Mössbauer Study of U₂Fe₁₂Al₅

et al. 2002

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The U 2 Fe 12 Al 5 compound was prepared by arc melting, followed by annealing at 850°C. This compound crystallizes in a structure derived from the Th 2 Ni 17 -type, (space group P6 3 / mmc, a ) 8.5631(7) and c ) 8.438(1) Å, R ) 0.050), with a partial delocalization of the uranium along the z-axis and with the iron atoms mainly located in the 6g and 12k positions. Magnetization measurements versus temperature indicate a ferromagnetic-type behavior below 295 K and a much less pronounced anomaly at 168 K, which was related with the existence of UFe 2 -based impurities. Measurements on magnetically oriented powder reveal that U 2 Fe 12 Al 5 has a uniaxial anisotropy, with c as easy axis. At 2 K the anisotropy constant values are K 1 ) 203 kJm -3 , K 2 ) 515 kJm -3 , and K 3 ) -132 kJm -3 , and the spontaneous magnetization takes the 16.6 µ B /fu value, significantly lower than the observed in R 2 Fe 12 Al 5 with the nonmagnetic RdCe and Y. The 57 Fe Mössbauer study shows that the hyperfine fields are smaller than in the similar R 2 Fe 12 Al 5 compounds (R ) Ce, Nd, Sm, and Tm). The magnetic and Mössbauer results are discussed in terms of the interatomic distances and iron site preferences.

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Section: H Mmentioning

confidence: 98%

Structural, Magnetic, and Mössbauer Study of U₂Fe₁₂Al₅

et al. 2002

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“…Therefore, it could be assumed that the main contribution to the Curie temperature in all compounds in the present series is due to the Fe-Fe exchange interaction. Dunlap et al 25 also have reported that the Curie tem- perature of the RE 2 Fe 17 compounds is primarily dependent on the magnitude of J TT and that both J RT and J RR are substantially smaller than J TT and are relatively independent of interatomic distances. Jacobs et al 24 have calculated the Fe-Fe exchange coupling constants of Y 2 Fe 17Ϫ x Al x for different Al concentrations and have found that there is an increase in the J Fe-Fe values with x, in the initial Al concentration range.…”

Section: Resultsmentioning

confidence: 95%

Structural, magnetic, and electrical properties of (Pr0.5Er0.5)2Fe17−xAlx

Suresh

Rao

1996

Journal of Applied Physics

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An x-ray diffraction study of (Pr0.5Er0.5)2Fe17−xAlx (0≤x≤10) shows an expansion of its unit cell with x. The crystal structure changes from hexagonal Th2Ni17 to rhombohedral Th2Zn17 at x=6. The magnetic moment decreases by increasing the Al concentration. This effect may be due to the charge transfer from Al to the 3d band of Fe. The Curie temperatures are found to increase with Al up to x=3 and then decrease up to x=10, and the possible underpinning mechanisms are discussed. X-ray diffractograms of the magnetically aligned samples indicate that the easy magnetization directions of the samples with x=1,2,3, and 4 lie on a cone about the c axis. Electrical resistivity measurements show that the residual resistivity increases drastically with the Al concentration. The temperature coefficient of resistivity becomes almost zero for intermediate Al concentrations.

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“…Moreover, the magnetic properties of the compounds are improved drastically by interstitial insertion of light elements such as carbon [3] whose thermal stability is better than the nitrides [4,5], leading to the resurgence of the interest in the investigation of R 2 Fe 17 compounds and their substitutional R 2 Fe 17Àx M x , as well as their metastable phases. The substitution of Fe by Al or Ga leads to a change of the system anisotropy from planar to uniaxial [6][7][8]. A Curie temperature enhancement was observed depending on both, M and x amount containing compounds [9] improved by nitrogen or carbon insertion [10].…”

Section: Introductionmentioning

confidence: 87%