Silver, R. N. and McGill, T. C. (1974) Spin-excitation spectra and resistance minima in amorphous ferromagnetic alloys. Physical Review B, 9 (1). pp. 272-280. ISSN 0556-2805. http://resolver.caltech.edu/CaltechAUTHORS:SILprb74
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Resistance minima have been found in recent years to occur in amorphous ferromagnetic alloys below the magnetic ordering temperature. Although a well-developed theory exists for resistance minima in very dilute alloys, the meaning of the phenomena has remained in question for alloys in which the neglect of spin-spin interactions is not justifiable. In this paper it is shown that the observation of resistance minima implies that these alloys have a finite density of near zero frequency excitations. Specifically, the theory of inverse transport coefficients, reformulated in terms of linear response, is used to derive a general expression for the resistivity due to the conduction-electron-spin interaction. Expanding perturbatively, the nth-order contribution is determined by an nth-order spin correlation function. To third order it is shown that the coefficient of the lnk T term responsible for the resistance anomaly according to the accepted Kondo theory receives contributions in the low-temperature limit only from those parts of the spin correlation functions which have frequencies less than k TK /ℏ where TK is the Kondo temperature.
|Additional Information:||© 1974 by The American Physical Society. Received 4 September 1973. We would like to express our appreciation to Dr. Anupam Madhukar for conversations which first stimulated our interest in this problem and for kindly sending us a preprint of his work. Helpful conversations with Dr. C.C. Tsuei are also gratefully acknowledged. Research supported in part by the Air Force Office of Scientific Research under Grant No. 73-2490. [R.N.S. was an] IBM Postdoctoral Fellow.|
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|Deposited By:||Tony Diaz|
|Deposited On:||15 May 2008|
|Last Modified:||26 Dec 2012 10:01|
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