M$ouml$ssbauer studies of the cubic Laves iron-rare-earth intermetallic compounds

Bowden, G. J.; Bunbury, D St P; Guimarães, A.P.; Snyder, R. E.

doi:10.1088/0022-3719/1/5/328

Cited by 140 publications

(39 citation statements)

References 16 publications

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“…In our fitting we used this model [3,13], where the relative intensity for the two magnetic components is 3:1 for GdFe 2 and this relative intensity increases with increasing the Hf concentration, as shown in Table 1. The ratio of 3:1 for the parent compound, GdFe 2 , is in agreement with previous results by Bowden et al [14], Wertheim and Wernick [15], and Wertheim et al [16] for GdFe 2 . The increase in the relative intensity as we increase x indicates that Hf occupies preferentially one of the two iron sites (the one with the lower intensity and lower magnetic hyperfine field).…”

Section: Resultssupporting

confidence: 92%

“…The subspectra in the top represent the subspectra for the sample with x = 0 at 300 K and at 78 K, the other samples have similar subspectra Velocity (mm/s) Table 1 The Mössbauer parameters at room temperature for GdFe 2−x Hf x alloys The quadrupole shifts (=2ε) for all the samples were 2ε − 1 = 0.14 (mm/s) and 2ε − 2 = −0.24 (mm/s). The line widths for the first three lines of each subspectra were fixed to the values of .40, 0.36, and 0.30 mm/s for all the samples H hf hyperfine magnetic field in (kOe), δ isomer shift in (mm/s), A percentage area (relative intensity) in (%) in the number of subspectra at room temperature and at 78 K indicates that the direction of magnetization in this system of alloys is along the [111] direction at room temperature, while it has a more complicated direction of magnetization at 78 K. This behavior is in agreement with previous observations by Bowden et al [14] for GdFe 2 and SmFe 2 measured at room temperature and at 77 K. The average magnetic hyperfine field for the different Hf concentrations is shown in Fig. 3.…”

Section: Resultssupporting

confidence: 91%

“…The average magnetic hyperfine field for the parent compound is 218 kOe. This value is in agreement with the value of 215 kOe for GdFe 2 found Table 2 The Mössbauer parameters at room temperature for GdFe by Bowden et al [14]. The decrease in the average magnetic hyperfine field with increasing the Hf concentration can be attributed to the substitution of magnetic element (Fe) by the non-magnetic element (Hf).…”

Section: Resultssupporting

confidence: 90%

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Mössbauer studies of GdFe2 − x Hf x alloys

et al. 2008

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GdFe 2−x Hf x alloys, where x = 0, 0.10, 0.15, 0.20, and 0.30, are produced by arc-melting of pure elements. The samples are investigated by x-ray diffraction and Fe 57 Mössbauer spectroscopy at 78 K and 300 K. We find that the alloy system GdFe 2−x Hf x have the single phase cubic Cu 2 Mg type structure in the whole concentration range. Mössbauer spectroscopic results show that all the samples studied are magnetically ordered at 78 K, and at room temperature. The room temperature spectra are fitted with two magnetic components where the direction of magnetization is along the [111] while the spectra at 78 K are fitted with four magnetic subspectra indicating a complex direction of magnetization for all samples under investigation. The average magnetic hyperfine field and the average isomer shift are found to decrease almost linearly with increasing the Hf concentration at 78 K and 300 K due to the replacement of Fe by nonmagnetic Hf.

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 90%

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Mössbauer studies of GdFe2 − x Hf x alloys

et al. 2008

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“…57 Fe Mössbauer study of the rare-earth iron alloys R 1 1−x R 2 x Fe 2 [11][12][13] has revealed that they possess several different types of spectra even though these compositions have identical crystallographic structures. Each of these spectra results from a different direction of easy magnetization relative to the crystallographic axes of the unit cell [14] . With the easy magnetization direction (EMD) along [100], all iron sites are equivalent and a simple six-line spectrum is obtained, as was observed for HoFe 2 and DyFe 2 .…”

Section: Introductionmentioning

confidence: 99%

Structure, spin reorientation and Mössbauer effect studies of Tb0.3Dy0.7(Fe1−x Alx)1.95 alloys

et al. 2006

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The effect of Al substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation of a series of polycrystalline Tb 0.3 Dy 0.7 (Fe 1−x Al x ) 1.95 alloys (x = 0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35) at room temperature and 77 K was investigated systematically. It was found that the primary phase of Tb 0.3 Dy 0.7 (Fe 1−x Al x ) 1.95 is the MgCu 2 -type cubic Laves phase structure when x < 0.4 and the lattice constant a of Tb 0.3 Dy 0.7 (Fe 1−x Al x ) 1.95 increases approximately and monotonically with the increase of x. The substitution of Al leads to the fact that the magnetostriction λ inceases slightly in a low magnetic field (H ≤ 40 kA/m), but decreases sharply and is easily close to saturation in a high applied field as x increases, showing that a small amount of Al substitution is beneficial to a decrease in the magnetocrystalline anisotropy. It was also found that the spontaneous magnetostriction λ 111 decreases greatly with x increasing. The analysis of the Mössbauer spectra indicated that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry with the changes of composition and temperature, namely spin reorientation. A small amount of non-magnetic phase exists for x = 0.15 in Tb 0.3 Dy 0.7 (Fe 1−x Al x ) 1.95 alloys and the alloys become paramagnetic for x > 0.15 at room temperture, but at 77 K the alloys still remain magnetic phase even for x = 0.2. At room temperature and 77 K, the hyperfine field decreases and the isomer shifts increase with Al concentration increasing.

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“…and (ii) (Cohen 1964, Bowden et al 1968, Atzmony and Dariel 1973, 1976 etc, (e.g. Abragam andBleaney 1970, Hutchings 1964) but rather the set of tensor operators T n q given by Buckmaster et al (1972), Bowden and Hutchison (1986 (Bowden and Hutchison 1986).…”

Section: Theory: Magneto-crystalline Magnetic Anisotropymentioning

confidence: 99%

Magnetic anisotropy terms in [110] MBE-grown REFe₂films involving the strain term ε_xy

Bowden

Groot

Rainford

et al. 2006

J. Phys.: Condens. Matter

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The magnetic anisotropy parameters in [110] MBE-grown films of REFe 2 (RE, rare earth) compounds are not the same as those in the bulk. This is due to the presence of a shear strain ε xy , frozen-in during crystal growth. In this paper, magnetic anisotropy parameters for [110] MBE-grown REFe 2 films, that directly involve the shear strain ε xy , are presented and discussed. In addition to the usual first-order Callen and Callen termK 2 , there are nine second-order terms, six of which involve cross-terms between ε xy and the cubic crystal field terms B 4 and B 6 . Two of the second-order cross-terms are identified as being important:K 242 (T ) andK 264 (T ). Of these, the rank-two termK 242 (T ) dominates over a large temperature range. It has the same angular dependence as the first-order termK 2 , but with a more rapid temperature dependence. The correction at T = 0 K for TbFe 2 , DyFe 2 , HoFe 2 , ErFe 2 and TmFe 2 , amounts to ∼+9.2%, −13.9%, −11.6%, +14.3%, and 27.1%, respectively. Similar comments are made concerning the rank-fourK 264 (T ) term.

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M$ouml$ssbauer studies of the cubic Laves iron-rare-earth intermetallic compounds

Cited by 140 publications

References 16 publications

Mössbauer studies of GdFe2 − x Hf x alloys

Mössbauer studies of GdFe2 − x Hf x alloys

Structure, spin reorientation and Mössbauer effect studies of Tb0.3Dy0.7(Fe1−x Alx)1.95 alloys

Magnetic anisotropy terms in [110] MBE-grown REFe₂films involving the strain term ε_xy

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M$ouml$ssbauer studies of the cubic Laves iron-rare-earth intermetallic compounds

Cited by 140 publications

References 16 publications

Mössbauer studies of GdFe2 − x Hf x alloys

Mössbauer studies of GdFe2 − x Hf x alloys

Structure, spin reorientation and Mössbauer effect studies of Tb0.3Dy0.7(Fe1−x Alx)1.95 alloys

Magnetic anisotropy terms in [110] MBE-grown REFe2films involving the strain term εxy

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Magnetic anisotropy terms in [110] MBE-grown REFe₂films involving the strain term ε_xy