Physica B: Condensed Matter 219-220, 284 (1996)

P. Esquinazi, R. König, B. Neppert, F. Pobell

Abstract

We have measured the sound velocity and sound attenuation of the dilute spin glasses Pd + 15 ppm Fe, Pd + 150 ppm Fe, and Pt + 55 ppm Fe at ~ 1 kHz and temperatures from 0.2 mK to 200 mK, 6 mK to 100 mK, and 50 mK to 200 mK, respectively. Both acoustic properties show anomalies near their spin glass freezing temperatures. For the most dilute sample Pd + 15 ppm Fe, we measured an attenuation peak at 1 mK accompanied by a maximum in the sound velocity. Both anomalies are suppressed by a magnetic field of only 0.1 mT.