ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Measurements of the critical behavior of the magnetic resonance linewidths ΔHpp from thin Ni(111) films on W(110) ranging in thickness from 15 to 40 A(ring) are presented. A huge peaklike broadening of ΔHpp is observed over a narrow temperature interval near the thickness-dependent Curie temperature TC(d). This peak results from the critical "speeding up'' of the relaxation rate Γ ∝ ΔHpp near TC due to spin fluctuations. This finding is discussed in relation to results on Gd monolayers, which show no critical broadening of the resonance linewidth. From the peak in ΔHpp, we directly determine TC(d), e.g., TC(15 A(ring))=512 K, and the shift exponent λ=1.42±0.3 for the thickness dependence of TC. Below TC, ΔHpp is analyzed in terms of the Landau–Liftshitz equation of motion, which yields ΔHpp ∝ (1 − T/TC)−β, with β the critical exponent of the spontaneous magnetization. A power law with β ranging from β=0.38 (bulk Ni) to 0.29 (15 A(ring)) is found for ≈ 10−3 ≤ (1 − T/TC) ≤ 6 × 10−2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.348176
Permalink
