Cluster specific heats in copper-rich Cu-Ni alloys: The effect of iron

Falge, R. L.; Wolcott, N. M.

doi:10.1007/bf00628414

Cited by 42 publications

(12 citation statements)

References 24 publications

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“…Finally, at the critical concentration (about 47.53,Ni), the correlation range will tend to infinity and result in bulk ferromagnetism. The giant moment behaviour at the critical point has been discussed by Hicks (1977) and the existence of magnetic clusters at this composition and well into the paramagnetic regime is evidenced by specific heat (Robbins er al 1969b, Schroder 1961, Dixon et al 1968, Fagle and Wolcott 1971 and magnetic susceptibility data (Pugh and Ryan 1958, Ryan et a / 1959, Kouvel and Comly 1970, Mishra er al 1970. Mishra 1974, Claus 1975.…”

Section: Introductionmentioning

confidence: 85%

Image of local density of states in differential conductance fluctuations in the resonance tunneling between disordered metals

Fal'ko

1998

Phys.-Usp.

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The effects of co-existing atomic and magnetic clustering on electrical resistivity are considered. It is shown that in Cu-Ni alloys such clustering produces competing effects and that while atomic clustering dominates the behaviour in alloys containing more than about 25"" Ni. the magnetic clustering effects are predominant in lower Ni content alloys. This results in a resistivity which decreases with increased clustering in alloys with more than 25"" Ni but which increases with clustering at lower Ni contents. This change in behaviour results from the non-linear dependence of the magnetic moments of the Ni-rich clusters upon composition and degree of clustering, which is due in turn to the dependence of the magnetic state of the Ni atoms upon their near-neighbour environment.

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Section: Introductionmentioning

confidence: 85%

Image of local density of states in differential conductance fluctuations in the resonance tunneling between disordered metals

Fal'ko

1998

Phys.-Usp.

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“…In the former case the magnetic heat capacity C M is predicted to vary as Tin T in the low temperature limit (Makoshi and Moriya 1975). However, experimental measurements in zero and applied magnetic fields have revealed Schottky-like maxima in CM (Falge and Wolcott 1971;Aitken et al 1981) which may be more readily explained in terms of superparamagnetic clusters.…”

Section: Introductionmentioning

confidence: 97%

“…Another view relates the magnetic ordering to spin glass freezing (Ododo and Coles 1977;Aitken et al 1981). Falge and Wolcott (1971) have also argued that the magnetic heat capacity in their study of Ni-Cu alloys could result from a cooperative ordering of the magnetic clusters.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Studies and Magnetic Ordering of Ni-Cr Alloys Close to the Critical Composition

Simpson¹,

Smith²

1982

Aust. J. Phys.

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We report measurements of the specific heat capacity and the thermal expansion for Ni-Cr alloys in the vicinity of the magnetic ordering temperature TM and at lower temperatures. No evidence of a contribution due to the magnetic ordering is found in the specific heat capacity and only the indication of a small contribution in the thermal expansion near to T M for an Ni 11 at. % Cr alloy.A significant contribution of magnetic origin is seen for both quantities at lower temperatures.Values for the magnetic Grlineisen parameter yi, are derived from the specific heat capacity and thermal expansion data and compared with values of dIn TM/d In V obtained from direct measurements of dTM/dP. Both yi, and -d In TM/d In V are large and negative for weakly ferromagnetic alloys but differ numerically, whereas for paramagnetic alloys yi, is large and positive.

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“…These inhomogeneities can be detected by heat capacity measurements at low temperatures. As first pointed out by Schr6der and Cheng [2], and later by many other investigators [3], for alloys with at least one element being iron, cobalt or nickel, the low-temperature heat capacity often contains a contribution due to magnetic clusters, which form in paramagnetic matrix, reflecting compositional inhomogencities. The results of this work show the presence of such inhomogeneities in all of the superalloys investigated.…”

mentioning

confidence: 97%

“…Since then, many alloys that contain at least one magnetic element including iron, cobalt and nickel have been known to exhibit similar heat capacity anomalies. Several theoretical models have been proposed ( [3] and references cited therein). Basically, these magnetic clusters, reflecting compositional inhomogeneities of submicroscopic scale not often observable through standard metallurgical techniques, form in a paramagnetic matrix near the critical composition for ferromagnetism.…”

mentioning

confidence: 99%