Origin of the Invar effect in iron–nickel alloys

Schilfgaarde, Mark van; Abrikosov, Igor A.; Johansson, Börje

doi:10.1038/21848

Cited by 501 publications

(381 citation statements)

References 22 publications

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“…1, is known to soften the lattice. 15 Since the amplitude of the local magnetic moments is less sensitive to volume conserving distortions, the softening is absent in shearing, as described by C 44 and ͑C 11 − C 12 ͒ / 2, but is present as the volume changed during uniform compression for the determination of the bulk modulus. Since the bulk modulus 21 is defined as…”

Section: ͑2͒mentioning

confidence: 99%

“…͑C 11 − C 12 ͒ / 2 is also independent of the Mn content, while C 11 and C 12 exhibit This is consistent with the previous work. 2 The behavior of the elastic constants can be understood based on the socalled magnetovolume effect 15 observed in our calculations. The strong dependence of local magnetic moments on lattice parameter ͑or volume͒, as shown in Fig.…”

Section: ͑2͒mentioning

confidence: 99%

“…The dependence of magnetic moments on volume is similar to their behavior in Fe-Ni Invar alloys. 15 Figure 2 shows the total energy for the DLM and NM Fe 0.60 Mn 0.40 configurations as a function of lattice parameter. It is evident that there are fundamental differences between the binding energy vs lattice parameter behavior for these two solutions.…”

Section: ͑2͒mentioning

confidence: 99%

“…Note that following Ref. 15, we used a cubic spline fitting procedure in order to account for the anomalous two-branch shape of the binding energy curve. Since the experimental value is 123 GPa, 1 the DLM configuration is closer to the measurement ͑7.9% deviation͒.…”

Section: ͑2͒mentioning

confidence: 99%

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Elastic properties of Fe–Mn random alloys studied by ab initio calculations

Mušić

Takahashi

Vitos

et al. 2007

Applied Physics Letters

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We have studied the influence of the Mn content on the elastic properties of Fe–Mn random alloys (space group of Fmm) using ab initio calculations. The magnetic effects in Fe–Mn alloys have a strong influence on the elastic properties, even above the Néel temperature. As the Mn content is increased from 5 to 40 at. %, the C44 elastic constant is unaffected, while C11 and C12 decrease. This behavior can be understood based on the magnetovolume effect which softens the lattice. Since the amplitude of local magnetic moments is less sensitive to volume conserving distortions, the softening is not present during shearing.Original publication: Denis Music, Tetsuya Takahashi, Levente Vitos, Christian Asker, Igor A. Abrikosov and Jochen M. Schneider, Elastic properties of Fe–Mn random alloys studied by ab initio calculations, 2007, Applied Physics Letters, (91), 191904. Copyright: The America Institute of Physics, http://www.aip.org

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Section: ͑2͒mentioning

confidence: 99%

Section: ͑2͒mentioning

confidence: 99%

Section: ͑2͒mentioning

confidence: 99%

Section: ͑2͒mentioning

confidence: 99%

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Elastic properties of Fe–Mn random alloys studied by ab initio calculations

Mušić

Takahashi

Vitos

et al. 2007

Applied Physics Letters

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“…1 Nevertheless, some issues, especially those related with iron in a face centered cubic ͑fcc͒ lattice, the so-called ␥-Fe, are still a hot topic of discussion at the present. 2,3 Total-energy band calculations predict a very rich and complex magnetic phase diagram, 4,5 including the presence of large moment-volume instabilities, [6][7][8] responsible for the existence of Invar and anti-Invar behaviors. Contrary to the Invar effect, where a nearly zero thermal expansion is observed in some magnetically ordered materials, other systems exhibits, in the paramagnetic state, an anomalous thermal expansion larger than that described by a Grüneisen lattice.…”

Section: Introductionmentioning

confidence: 99%

High-temperature induced ferromagnetism onγ−Feprecipitates in FeCu solid solutions

et al. 2005

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Thermoresponsive Inorganic Materials

Evans

2002

Encyclopedia of Smart Materials

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The effect of temperature on the vast majority of materials is well known—as materials are heated, they initially expand in volume before eventually melting, subliming, or decomposing. Thermal expansion is often viewed as a deleterious property. Thermal expansion can, however, also be put to good use. It has long been known that the walls of bowed buildings can be pulled back into shape by a cooling iron bar; steel tires can be shrink‐fitted onto the wheels of railway carriages. Although these examples represent a technologically useful response to the stimulus of increased (or decreased) temperature, they do not quite fall into the category of “smart.” However, the very simple concept of coupling together two materials, one that has a large and one a smaller coefficient of thermal expansion to produce a bimetallic strip can certainly be considered to create a smart composite body. Here, the strains induced by the higher expansion of one material cause the strip to bend as temperature is increased, leading to a simple temperature‐sensing/responsive device. The vast majority of materials known and used in technological applications have a positive coefficient of thermal expansion; the reasons for this behavior are discussed. Certain materials, however, display the opposite property and contract in volume when heated. These materials thus have a negative coefficient of thermal expansion, which has led to their somewhat confusing description as “negative thermal expansion” (NTE) materials. The properties of these materials and the origin of these effects form the main topic of this article. Materials that have this unusual thermoresponse have a number of important technological applications. Applications related to specific materials are discussed. The first major area of application is in producing composite bodies. By mixing normal materials with a negative thermal expansion phase, one can achieve a composite that has a precisely controlled positive, negative, or even zero coefficient of expansion. Second, certain of the materials discussed can be chemically doped to control their expansion properties. Thus, one can envisage a single material that could be adjusted to have zero overall expansion. Such materials are of use where repeated thermal shock might lead to mechanical failure (an everyday example is oven‐to‐table cookware) or in optical devices such as high precision mirrors where any thermal expansion might distort optical properties. Materials that have strong intrinsic thermal contraction are most likely to be used as compensators for the positive expansion of other phases. In “negative thermal expansion” materials considered in the remainder of this article, there will always be an underlying expansive component caused by vibrational modes that tend to increase bond distances. In certain circumstances, however, these modes may be dominated by other more exotic effects.

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Origin of the Invar effect in iron–nickel alloys

Abstract: wave pairing near a spin-density-wave instability.

Cited by 501 publications

References 22 publications

Elastic properties of Fe–Mn random alloys studied by ab initio calculations

Elastic properties of Fe–Mn random alloys studied by ab initio calculations

High-temperature induced ferromagnetism onγ−Feprecipitates in FeCu solid solutions

Thermoresponsive Inorganic Materials

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