Spin-Orientation Diagrams and Magnetic Anisotropy of Rare-Earth-Iron Ternary Cubic Laves Compounds

Atzmony, U.; Dariel, M.P.; Bauminger, E. R.; Lebenbaum, D.; Nowik, I.; Ofer, S.

doi:10.1103/physrevb.7.4220

Cited by 189 publications

(71 citation statements)

References 10 publications

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“…The predicted remanence behavior is compared with the one of a Tb 0.6 Ho 0.4 Fe 2 sample, a rare-earth iron Laves compound representing spin-reorientation transition of the easiest direction of magnetization [19][20][21] from ͗110͘ to ͗111͘ in the vicinity of 85 K.…”

Section: Comparison With the Experimentsmentioning

confidence: 99%

“…Both K 1 and K 2 are temperature dependent, K 1 can pass through zero at a certain temperature, so the ͉K 2 /K 1 ͉ ratio can be very high in some temperature range; in such cases one must take into account the term containing K 2 in the energy expression in order to explain the magnetic behavior of the material. Rare-earth iron garnets 18 and rare-earth iron ternary cubic Laves phase compounds [19][20][21] are examples of such magnetic systems. Some numerical results on the influence of K 2 on the hysteresis loops of noninteracting single domain particles have been reported by Usov and Peschany 7 and by García-Otero et al 22 In this article, we present detailed model calculations of the magnetization and remanence curves for a disordered system of noninteracting single-domain particles with cubic anisotropy, taking into consideration both the first and the second anisotropy constants.…”

Section: Introductionmentioning

confidence: 99%

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Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

Geshev

Pereira

Schmidt

et al. 2001

Journal of Applied Physics

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Magnetization and remanent magnetization curves for noninteracting single-domain particles with cubic magnetocrystalline anisotropy have been calculated, taking into account the first two anisotropy constants. The dependencies of the saturation remanence, coercivity, remanence coercivity, and ␦M plots on the anisotropy constants ratio have been discussed. It has been found that the calculated saturation remanence shows maxima in the vicinity of the spin-reorientation transition points for both negative and positive first cubic anisotropy constants. The remanent magnetization for the case when the face diagonals ͗110͘ are the easiest magnetization orientations has been analytically determined as well. It has been shown that when more than one type of easiest directions coexist, the remanence of the system can only be obtained numerically because of the history dependence of the remanent magnetization for some particles' configurations. The predicted remanence behavior for systems representing spin-reorientation has been compared with that of a Tb 0.6 Ho 0.4 Fe 2 powder sample, and an excellent agreement between numerical and experimental data has been found.

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Section: Comparison With the Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

Geshev

Pereira

Schmidt

et al. 2001

Journal of Applied Physics

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“…Therefore, a kind of excellent and potential giant magnetostrictive material would be developed. 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] .…”

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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“…Following Cohen (1964), Bowden et al (1968), Atzmony et al (1973), and Atzmony and Dariel (1976), the Hamiltonian at the RE ion can be written…”

Section: The Hamiltonian For the Re Ion In The Refe 2 Compoundsmentioning

confidence: 99%

“…Instead, values of K 1 etc have been determined indirectly, primarily from experiments on polycrystalline samples. For example, during the mid-1970s, exhaustive 57 Fe Mössbauer studies were used to determine the directions of easy magnetization in mixed RE intermetallic compounds of the form RE(a) 1−x RE(b) x Fe 2 (Atzmony et al 1973(Atzmony et al , 1976, hereafter referred to as A&D). In particular, spin-orientation diagrams (SODs) were prepared, and used to determine values of the crystal field parameters B 4 and B 6 , for the differing RE ions.…”

Section: K N Martin Et Almentioning

confidence: 99%

Magnetic anisotropy in the cubic Laves REFe₂intermetallic compounds

Martin

Groot

Rainford

et al. 2005

J. Phys.: Condens. Matter

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In the past, the Callen-Callen (1965 Phys. Rev. 139 A455-71; J. Phys. Chem. Solids 27 1271-85) model has been highly successful in explaining the origin and temperature dependence of the magneto-crystalline anisotropy in many magnetic compounds. Yet, despite their high ordering temperatures of ∼650 K, the Callen-Callen model has proved insufficient for the REFe 2 compounds. In this paper, we show that it is possible to replicate the values of the phenomenological parameters K 1 , K 2 , and K 3 given by Atzmony and Dariel (1976 Phys. Rev. B 13 4006-14), by extending the CallenCallen model to second order in H CF . In particular, explanations are provided for (i) the unexpected changes in sign of K 1 and K 2 in HoFe 2 and DyFe 2 , respectively, and (ii) the origin and behaviour of the K 3 term. In addition, it is demonstrated that higher order terms are required,and that K 4 exceeds K 3 at low temperatures. Revised estimates of K 1 , K 2 , K 3 , K 4 , and K 5 are given. Finally, an alternative 'multipolar' approach to the problem of magnetic anisotropy is also provided. It is shown that the latter confers significant advantages over the older phenomenological method. In particular, all the multipolar coefficients (K N , N = 4, 6, 8, 10, 12) decrease monotonically with increasing temperature, withK N decreasing faster thanK N −2 etc. These observations are in accord with expectations based on the original Callen-Callen model.

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Spin-Orientation Diagrams and Magnetic Anisotropy of Rare-Earth-Iron Ternary Cubic Laves Compounds

Cited by 189 publications

References 10 publications

Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

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

Magnetic anisotropy in the cubic Laves REFe₂intermetallic compounds

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Spin-Orientation Diagrams and Magnetic Anisotropy of Rare-Earth-Iron Ternary Cubic Laves Compounds

Cited by 189 publications

References 10 publications

Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

Dependence of the magnetization and remanence of single-domain particles on the second cubic anisotropy constant

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

Magnetic anisotropy in the cubic Laves REFe2intermetallic compounds

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Magnetic anisotropy in the cubic Laves REFe₂intermetallic compounds