Abstract
The ESR of the spin glassAgMn (2.7 and 9.6 at %) has been investigated below and aboveT g(0.1T g<T<5T g) at various microwave frequencies. The analysis yields:1) No explicit frequency dependence but strong magnetic field effects, inherent with ESR-experiments.2) Part of the excess line width is identified as critical spin fluctuations, following a power law. However, because of the presence of the applied field, the reduced temperaturet is not a good scaling variable. We choose the non-linear susceptibility X s divided byH 2, which scales as the order parameter susceptibility. The experiment yieldsW ex∞(X s /H 2)p,p=0.42. From this we deduce νz≈3.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
For a review see Fischer, K.H.: Phys. Status Solidi (b)130, 13 (1985)
Mozurkewich, G., Elliot, J., Hardiman, M., Orbach, R.: Phys. Rev. B29, 278 (1984)
Salamon, M.B., Herman, R.M.: Phys. Rev. Lett.41, 1506 (1978)
Wei-yu Wu, Mozurkewich, G., Orbach, R.: Phys. Rev. B31, 4557 (1985)
Saslow, W.M.: Phys. Rev. B30, 461 (1984)
Becker, K.W.: Phys. Rev. B26, 2394 and 2409 (1982)
Levy, P.M., Morgan-Pond, C., Raghavan, R.: Phys. Rev. Lett.50, 1160 (1983); Phys. Rev. B30, 2358 (1984)
Barnes, S.E.: Adv. Phys.30, 801 (1981)
Kawasaki, K.: Prog. Theor. Phys.39, 285 (1968)
Huber, D.L.: J. Phys. Chem. Solids32, 2145 (1971)
Suzuki, M.: Prog. Theor. Phys.58, 1151 (1977)
Chalupa, J.: Solid State Commun.22, 315 (1977) and24, 429 (1977)
Malozemoff, A., Barbara, B.: J.A.P.57, 3410 (1985)
Dyson, F.J.: Phys. Rev. B98, 349 (1955)
Levy, P.M., Morgan-Pond, C., Fert, A.: J. Appl. Phys.53, 2168 (1982)
Zomack, M., Baberschke, K., Barnes, S.E.: Phys. Rev. B27, 4135 (1983)
The separation of the experimental linewidthW intoW Korringa andW spin-spin is not completely clear close toT +g . In the literature [2, 4, 6, 7, 13] one commonly adds the two contributions. We will follow this line (see Eq. 4). There is no controversy that the residual widtha (ora *) has to be substracted. For our system and in the vicinity ofT +g , ℓT is not large and changes only slowly with temperature. However we note that a different analysis of the linewidth is possible and can be performed with the present data
Salamon, M.B.: Solid State Commun.31, 781 (1979)
Hohenberg, P.C., Halperin, B.I.: Rev. Mod. Phys.49, 435 (1977)
Fisher, M.E.: Rep. Prog. Phys.30, 615 (1967)
Bontemps, N., Rajchenbach, J., Chamberlin, R.V., Orbach, R.: Phys. Rev. B30, 6514 (1984); Bontemps, N., Rajchenbach, J., Chamberlin, R.V., Orbach, R.: ICM '85, 1A 1. J. Magn. Magn. Mater.54–57, 1 (1986)
Bouchiat, H.: J. Phys. (Paris)47, 71–88 (1986)
Bouchiat, H., Monod, P.: ICM '85; J. Magn. Magn. Mater54–57, 124 (1986)
For a review of the experimental results see: Tholence, J.L.: Proceedings of L.T. 17, Part II, 157 (1984)
For A.C. susceptibility measurements in applied fields see [19]
The “leveling off” of the linewidth in [2, 4] seems to be an artifact of the logt plot. Our raw data show no plateau atT g. Moreover the definition oft * in [4] looks somewhat arbitrary—we do not see the physical significance
Baberschke, K., Pappa, C., Mahdjour, H., Wendler, R.: ICM '85, 5B 5. J. Magn. Magn. Mater54–57, 179 (1986)
This should not be confused with another use of Φ:Φ*=β+γ
This was brought to our attention by A. Zippelius. We would like to thank A. Zippelius and K.H. Fischer for illuminating discussions
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mahdjour, H., Pappa, C., Wendler, R. et al. Field dependent critical fluctuations aboveT g in the ESR line width of the spin glassAgMn. Z. Physik B - Condensed Matter 63, 351–364 (1986). https://doi.org/10.1007/BF01303815
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01303815