Anomalous spectral density and two-level system-phonon coupling in an insulating magnetic glass

Abstract

2014 Des mesures ultrasonores aux basses températures, dans la gamme de fréquence 0,1-1 GHz ont été faites sur le verre magnétique (MnF2)0,65(BaF2)0,2(NaPO3)0,15. La densité spectrale, P des systèmes à 2 niveaux (S2N) est deux ordres de grandeur plus petite que dans les autres verres tandis que les constantes de couplage S2N-phonon 03B31 et 03B3t sont anormalement grandes. La comparaison avec les mesures effectuées sur le verre non magnétique (ZnF2)0,6(BaF2)0,2(NaPO3)0,2 suggère un lien entre ces valeurs anormales et les propriétés magnétiques du verre.

Acoustic susceptibility of some insulating spin-glasses

“…The data for the Co and Ni glasses are quite similar while, as expected, the Zn glass shows a genuine glass velocity variation. The behaviour of the Mn glass appears somewhat different because the glassy features are anomalous as discussed in a previous article [4]. 3.…”

“…The experiments on the Co and Ni compounds were performed with a new experimental set-up using a synthesizer. Consequently the accuracy of the recent measurements was improved by about one order of magnitude as compared to the older measurements on the Mn and Zn compounds [4].…”

“…In figure 3 results obtained on a manganese glass are also shown. They were published with an interpretation which neglected the spin-glass effect [4]. After we have performed our experiments on cobalt and nickel glasses, we revisited our first interpretation, slightly changing the TLS-parameter K3.…”

“…Acoustic susceptibility of some insulating spin-glasses P. Doussineau (1), A. Levelut (1), M. Matecki (2) and W. Schön (1) (1) Laboratoire d'Ultrasons (*), Université Pierre et Marie Curie, Tour 13,4 place Jussieu, 75252 Paris Cedex 05, France (2) Laboratoire de Chimie Minérale D (*), Université de 35042 Rennes Cedex, France (Reçu le 13 octobre 1988, accepté le 18 novembre 1988) Résumé. 2014 Des mesures de propagation acoustique à hautes fréquences ont été effectuées dans trois verres de spins isolants au voisinage de la température Tc de gel des spins.…”

“…Indeed the attention is focused on the nickel glass (NiF2),5(BaF2),2(NaP03).3 where the magnetic effects are the most spectacular. In addition, for the sake of comparison some results on the cobalt glass (CoF2).5(BaF2).2(NaP03)3, on the manganese glass (MnF2).65(BaF2)2(NaPO3) 15 and on the non-magnetic glass (ZnF2).6(BaF2).2(NaPO3).2 are recalled [4].…”