Electron state density and anomalies in the electronic and lattice properties of metals and alloys

Katsnelson, M. I.; Trefilov, A. V.

doi:10.1070/pu1988v031n03abeh005723

Cited by 5 publications

(6 citation statements)

References 12 publications

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“…These predictions of the theory are fulfilled by the present study on Cr-Ir alloys, as is also the case for other dilute Cr alloys [1]. Katsnel'son and Trefilov [33] found that the magnetic contributions to the thermal expansion and shear elastic constants should vary as (T N − T ) −1 if the density-of-states function in the paramagnetic phase is smooth near the Fermi level and as (T N − T ) −5/4 if it has a van Hove singularity there. The results of the present study on Cr-Ir alloys were however found not to fit any one of these two power laws.…”

Section: Discussionsupporting

confidence: 86%

“…Katsnel'son and Trefilov [33] recently studied the anomalies in the elastic constants and thermal expansion of Cr alloys theoretically. They considered the effects of the disappearance of the antiferromagnetic SDW energy gap in the electron spectrum on the electron screening and phonon spectrum of the alloys, and showed that the elastic constants should soften and that there is a negative contribution to the thermal expansion coefficient at T N .…”

Section: Discussionmentioning

confidence: 99%

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Magnetoelasticity of dilute Cr - Ir alloy single crystals

Martynova¹,

Alberts²,

Smit³

1997

J. Phys.: Condens. Matter

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Measurements are reported of the temperature dependence of the elastic constants, ultrasonic attenuation and thermal expansion of dilute Cr - Ir alloy single crystals containing 0.07, 0.17, 0.20 and 0.25 at.% Ir. Well defined magnetic anomalies were observed in the elastic constants and in the thermal expansion at the Néel points and at the incommensurate - commensurate (I - C) spin-density-wave (SDW) transition temperatures . The transition at , observed in Cr + 0.20 at.% Ir and Cr + 0.25 at.% Ir, is hysteretic, of hysteresis width about 20 K. Magnetic anomalies were also observed in the elastic constants at the spin-flip transition temperature , The attenuation coefficient shows a large spike-like peak at (on heating) and at (on cooling) for Cr + 0.20 at.% Ir. These peaks are however smeared out by inhomogeneities in the crystal containing 0.25 at.% Ir. The attenuation coefficient peaks at and in Cr + 0.07 at.% Ir and in Cr + 0.17 at.% Ir. Due to very large attenuation and the high value of could not be measured successfully around the Néel point for the other crystals. The magnetovolume and magnetic contributions to the bulk modulus (B) have been found to fit the equation , predicted by theory, rather well up to temperatures (T) close to . The volume derivative of calculated from and for Cr + 0.07 at.% Ir, compares fairly well with the value obtained from high-pressure measurements. High-pressure measurements are not available for the other crystals for a similar comparison. The temperature dependence of for Cr + 0.17 at.% Ir fits the power law , predicted by theory for T just above , rather well. The theory however fails in the case of Cr + 0.07 at.% Ir and could not be tested for the other two crystals.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Magnetoelasticity of dilute Cr - Ir alloy single crystals

Martynova¹,

Alberts²,

Smit³

1997

J. Phys.: Condens. Matter

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“…Magnetic anomalies in the elastic constants and thermal expansion of Cr alloys were recently studied theoretically by Katsnel'son and Trefilov [27]. They considered the effects of the disappearance of the antiferromagnetic SDW energy gap in the electron spectrum on the electron screening and phonon spectrum of the alloys, and showed that there is a negative SDW contribution to the thermal expansion coefficient at T N .…”

Section: Discussionmentioning

confidence: 99%

“…The theory furthermore predicts a softening in the elastic constants at T N with a much larger softening in B than in the shear constants. Katsnel'son and Trefilov [27] found that the magnetic contributions to the thermal expansion and to the shear constants should vary as (T N − T ) −1 if the density-of-states function in the paramagnetic phase is smooth near the Fermi level and as (T N − T ) −5/4 if it has a van Hove singularity there. These power laws are valid [27] if the temperature is not too close to T N .…”

Section: Discussionmentioning

confidence: 99%

Untitled

Prinsloo¹,

Alberts²,

Smit³

1997

J. Phys.: Condens. Matter

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Measurements are reported of the temperature dependence of the elastic constants, ultrasonic attenuation and thermal expansion of dilute Cr - Ga alloy single crystals containing 0.16, 0.42 and 0.88 at.% Ga. Well defined magnetic anomalies were observed in all of these physical properties at the Néel temperature , at the incommensurate - commensurate (I - C) spin-density-wave (SDW) transition temperature and at the spin-flip transition temperature . The complete magnetic phase diagram of the alloy system has been determined for x < 1 at.% Ga from the temperatures of these anomalies. The magnetovolume and the magnetic component to the bulk modulus were both found to vary as , as predicted by theory, in the ISDW phases of all three of the crystals. Values of the pressure derivatives of for the crystals containing 0.16 at.% Ga and 0.42 at.% Ga were calculated from the results for and calculated for the Cr + 0.16 at.% Ga crystal compares very well with the value obtained from direct high-pressure measurements. High-pressure measurements have not been made on the Cr + 0.42 at.% Ga crystal for a comparison. The value calculated from and for Cr + 0.88 at.% Ga does not compare well with obtained from direct high-pressure measurements. This may point to inadequacies in the thermodynamic model used for the calculations. Predictions of microscopic theories for the temperature dependence of the ultrasonic attenuation, magnetovolume and the magnetic components of the elastic constants close to do not fit the present measurements.

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“…A geometrical origin of DOS peaks in a general context, as well as its implementation for concrete compound electronic spectrum obtained within the density functional theory (DFT) were investigated in detail in Ref. [6]. In particular, in fcc phase of Sr, weakly dispersive one-dimension manifolds (their prototype is a van Hove line) are positioned at the face of the Brillouin zone near the Fermi level.…”

Section: Introductionmentioning

confidence: 99%