scholarly journals Magnetic Correlations in Spin Glasses above the Freezing Temperature investigated by High Field Mössbauer Spectroscopy

1998 ◽  
Vol 51 (2) ◽  
pp. 349 ◽  
Author(s):  
J. Bogner ◽  
H. Schachner ◽  
M. Reissner ◽  
W. Steiner
Keyword(s):  
External Field ◽  
Temperature Dependence ◽  
Power Law ◽  
Spin Glasses ◽  
High Field ◽  
Freezing Temperature ◽  
Hyperfine Fields ◽  
Magnetic Correlations ◽  
Neighbour Shell ◽  
Centre Shift

The strong dynamics of magnetic correlations are observed by high field 57Fe Mössbauer investigations for the spin glasses AuFe and Y(Fe, Al)2 in the temperature interval between the freezing temperature Tf and approximately 7 to 10Tf. All recorded spectra can be analysed with a model which takes into account these dynamics by allowing the formation of correlated states after a stochastically varying time τoff and their decay after a time τon, restricting the number of subspectra to the different number of Fe atoms in the first neighbour shell. Whereas for the different Fe environments, in addition to centre shift and quadrupole splitting, different hyperfine fields of the two stochastically formed states can always be resolved, the same set of τon and τoff values was obtained for all subspectra above approximately 4Tf. The external field hinders the decay of the correlated regions. The temperature dependence of ¿ on scales with Tf and exhibits a power law with exponents of –2 for the Fe-rich and –1 for the Fe-poor compounds.

scholarly journals MULTICANONICAL SPIN GLASS SIMULATIONS

1992 ◽  
Vol 03 (06) ◽  
pp. 1251-1274 ◽  
Author(s):  
BERND A. BERG ◽  
TARIK CELIK
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Lower Bound ◽  
Temperature Dependence ◽  
Spin Glass ◽  
Power Law ◽  
Spin Glasses ◽  
Spin Glass Model ◽  
Glass Model ◽  
Quantities Of Interest

We report a Monte Carlo simulation of the 2D Edwards-Anderson spin glass model within the recently introduced multicanonical ensemble. Replica on lattices of size L2 up to L=48 are investigated. Once a true groundstate is found, we are able to give a lower bound on the number of statistically independent groundstates sampled. Temperature dependence of the energy, entropy and other quantities of interest are easily calculable. In particular we report the groundstate results. Our data indicate that the large L increase of the ergodicity time is reduced to an approximately V3 power law. Altogether the results suggest that the multicanonical ensemble improves the situation of simulations for spin glasses and other systems which have to cope with similar problems of conflicting constraints.

scholarly journals Study of the de Almeida–Thouless Line Using Power-Law Diluted One-Dimensional Ising Spin Glasses

2009 ◽  
Vol 102 (17) ◽  
Author(s):  
Helmut G. Katzgraber ◽  
Derek Larson ◽  
A. P. Young
Keyword(s):  
Power Law ◽  
Spin Glasses ◽  
One Dimensional ◽  
Ising Spin

Temperature dependence of impurity hyperfine fields in ferromagnets

1970 ◽  
Vol 3 (10) ◽  
pp. 2151-2155 ◽  
Author(s):  
I A Campbell
Keyword(s):  
Temperature Dependence ◽  
Hyperfine Fields

scholarly journals Temperature dependence of the high-field magnetization in Fe-Ag granular alloys and discontinuous multilayers

2010 ◽  
Vol 200 (7) ◽  
pp. 072050
Author(s):  
L F Kiss ◽  
J Balogh ◽  
L Bujdosó ◽  
D Kaptás ◽  
F Tanczikó ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
High Field ◽  
Field Magnetization ◽  
High Field Magnetization ◽  
Granular Alloys

Magnetic correlations in two-dimensional spin-glasses

1980 ◽  
Vol 22 (1) ◽  
pp. 288-303 ◽  
Author(s):  
I. Morgenstern ◽  
K. Binder
Keyword(s):  
Spin Glasses ◽  
Two Dimensional ◽  
Magnetic Correlations

Magnetic properties of undoped and Co-doped n-type β–FeSi2.5 single crystals

2002 ◽  
Vol 17 (11) ◽  
pp. 2960-2965 ◽  
Author(s):  
E. Arushanov ◽  
L. Ivanenko ◽  
D. Eckert ◽  
G. Behr ◽  
U. K. Rößler ◽  
...  
Keyword(s):  
Activation Energy ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
External Field ◽  
Single Crystals ◽  
Spin Glasses ◽  
Paramagnetic Centers ◽  
Temperature Dependent ◽  
Paramagnetic Curie Temperature ◽  
Co Doped

Results of magnetization and magnetic susceptibility measurements on undoped and Co-doped FeSi2.5 single crystals are presented. The temperature dependence of the magnetic susceptibility of the Co-doped sample in the range of 5–300 K can be explained by temperature-dependent contributions due to paramagnetic centers and the carriers excited thermally in the extrinsic conductivity region. The values of the paramagnetic Curie temperature and activation energy of the donor levels were estimated. It is also shown that the magnetic susceptibility of Co-doped samples cooled in zero external field and in a field are different. This resembles the properties of spin-glasses and indicates the presence of coupling between magnetic centers.

The temperature dependence of hyperfine fields at impurities in Fe

1975 ◽  
Vol 5 (11) ◽  
pp. 2184-2190 ◽  
Author(s):  
Le Dang Khoi ◽  
P Veillet ◽  
I A Campbell
Keyword(s):  
Temperature Dependence ◽  
Hyperfine Fields

External field influence on the magnetic hyperfine fields in alpha-manganese

1990 ◽  
Vol 59 (1-4) ◽  
pp. 441-444 ◽  
Author(s):  
G. De Doncker ◽  
J. Van Cauteren ◽  
M. Rots
Keyword(s):  
External Field ◽  
Magnetic Hyperfine ◽  
Hyperfine Fields ◽  
Field Influence

Temperature dependence of the hyperfine fields in NiFe2O4 and CuFe2O4 oxides

HFI/NQI 2007 ◽  
2008 ◽  
pp. 93-99
Author(s):  
J. Z. Msomi ◽  
T. Moyo
Keyword(s):  
Temperature Dependence ◽  
Hyperfine Fields
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