Muon spin relaxation studies of the spin glass AgMn

Journal Article · Mon Mar 01 04:00:00 EST 1982 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.330771· OSTI ID:5585440

Heffner, R H; Leon, M; Schillaci, M E; MacLaughlin, D E; Dodds, S A

We report measurements of magnetic ion dynamics in the spin-glass sytem AgMn (1.6 at. %) using the muon spin relaxation technique (..mu..SR). The salient features of the theoretical ..mu..SR lineshapes in zero and finite longitudinal applied fields are reviewed. Zero-field measurements below the glass temperature (T/sub g/ = 7.6 K) exhibit a static width a(T) which decreases with increasing temperature reminiscent of an ''order parameter'' behavior. At T< or approx. =T/sub g//2 the static width is consistent with that calculated for a random orientation of frozen Mn spins. The temperature dependence of a(T) is attributed to rapid, small-amplitude fluctuations of the local field about its quasistatic equilibrium position. An apparent stiffening of the fluctuation frequency spectrum is observed as the applied magnetic field is increased. The measured upper limit for frequencies which significantly relax the muon spin is about 50--100 times smaller than the peak in the mode density calculated by Walstedt and Walker in Monte Carlo simulations of small-amplitude harmonic excitations in CuMn (0.9 at. %), a system similar to ours. Above T/sub g/ the spin motion changes dramatically, from small-amplitude fluctuations to nearly complete reorientation, as expected. Measurements in longitudinal fields above T/sub g/ confirm the anomalous field-induced static broadening reported in earlier transverse field measurements.

• Research Organization: Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 5585440
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 53:3; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals &amp; Alloys-- Physical Properties
ALLOYS
AMORPHOUS STATE
CRITICAL TEMPERATURE
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
MANGANESE ALLOYS
MUONS
PHYSICAL PROPERTIES
RELAXATION
SILVER ALLOYS
SILVER BASE ALLOYS
SPIN GLASS STATE
SPIN-SPIN RELAXATION
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE