An adaptive algorithm for n-body field expansions
Weinberg, Martin D.
1998-05-28
Search results
57 records were found.
Experiments on the time dependence of the response function of a Ag(11 at%Mn)
spin glass at a temperature below the zero field spin glass temperature are
used to explore the non-equilibrium nature of the spin glass phase. It is found
that the response function is only governed by the thermal history in the very
neighbourhood of the actual measurement temperature. The thermal history
outside this narrow region is irrelevant to the measured response. A result
that implies that the thermal history during cooling (cooling rate, wait times
etc.) is imprinted in the spin structure and is always retained when any higher
temperature is recovered. The observations are discussed in the light of a real
space droplet/domain phenomenology. The results also emphasise the importance
of using controlled cooling procedures to acquire interpretable an...
Comment: EPL style; 7 pages, 5 figures
Comment: EUROTeX style; 9 pages, 4 figures
Reply to the Comment by L. Berthier and J.-P. Bouchaud, Phys. Rev. Lett. 90,
059701 (2003), also cond-mat/0209165, on our paper Phys. Rev. Lett. 89, 097201
(2002), also cond-mat/0203444
Comment: 8 pages RevTEX, 5 figures
Comment: 6 pages, 7 figures
The diluted Ising antiferromagnet, Fe_{0.31}Zn_{0.69}F_{2}, has been
investigated by dynamic susceptibility measurements in zero and and finite
applied dc-fields. In zero field, there is a para- to antiferromagnetic phase
transition at $T_{N} \approx {20.0 K}$, followed by a dramatic slowing down of
the dynamics at low temperatures. The latter described by a pure Arrhenius law.
The effect of a superposed dc-field on the antiferromagnetic phase transition
and on the low-temperature dynamics is investigated, and a comprehensive static
and dynamic phase diagram in the H-T plane is derived. In agreement with
earlier results on the same system, $T_{N}(H)$ follows a random-exchange Ising
model to random-field Ising model crossover scaling for fields $H \leq 1.5 T$.
A random-field induced glassy dynamics appears for higher values of H, wher...
Non-equilibrium dynamics in an interacting Fe-C nanoparticle sample,
exhibiting a low temperature spin glass like phase, has been studied by low
frequency ac-susceptibility and magnetic relaxation experiments. The
non-equilibrium behavior shows characteristic spin glass features, but some
qualitative differences exist. The nature of these differences is discussed.
The magnetic and structural properties of oxygen-deficient perovskites with composition Ba3Fe2WO9-6 (BFWO) have been systematically studied for two different oxygen contents corresponding to delta = 0.00 and 0.55 in the chemical formula in order, to determine and correlate their chemical composition, structural and magnetic properties. The evolution of nuclear and magnetic structures with temperature has been investigated by neutron powder diffraction. It was shown that at room temperature the stoichiometric compound (delta = 0.00) adopts a hexagonal 6H-perovskite structure (space group P6(3)/mmc). This phase, when heated at high temperature under a stream of Ar gas, transforms to an oxygen-deficient phase delta = 0.55), which is an ordered cubic perovskite structure (space group Fm-3m). The crystallographic and magnetic properties of ...
