Activated dynamic scaling in spin glasses above the freezing temperature

1986 ◽  
Vol 34 (9) ◽  
pp. 6579-6581 ◽  
Author(s):  
A. P. Malozemoff ◽  
E. Pytte
1985 ◽  
Vol 57 (8) ◽  
pp. 3410-3412 ◽  
Author(s):  
A. P. Malozemoff ◽  
B. Barbara

1990 ◽  
Vol 67 (9) ◽  
pp. 5249-5251 ◽  
Author(s):  
S. Geschwind ◽  
D. A. Huse ◽  
G. E. Devlin

1998 ◽  
Vol 51 (2) ◽  
pp. 349 ◽  
Author(s):  
J. Bogner ◽  
H. Schachner ◽  
M. Reissner ◽  
W. Steiner

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.


1993 ◽  
Vol 48 (18) ◽  
pp. 13573-13578 ◽  
Author(s):  
Bénédicte Leclercq ◽  
Claudette Rigaux

2007 ◽  
Vol 998 ◽  
Author(s):  
Andrei V. Rode ◽  
Denis Arcon ◽  
Andrej Zorko ◽  
Zvonko Jaglicic ◽  
Andrew G. Christy ◽  
...  

ABSTRACTCarbon nanoclusters produced by high-repetition-rate laser ablation of graphite and glassy carbon in Ar exhibits para- and ferromagnetic behaviour at low temperature. The results show that the degree of remanent order is strongly dependent on the magnetic history, i.e. whether the samples were cooled under zero-field or field conditions. Such behaviour is typical for a spin glass structure where the system can exist in many different roughly equivalent spin configurations. The spin-freezing temperature is unusually high (50–300 K) compared with ≤ 15 K for typical spin glasses. The maximum in the zero-field magnetic susceptibility experiments and their field dependence indicate that there is competition between ferromagnetic and antiferromagnetic exchange pathways, accounting for the spin glass behavior and/or a low-dimensionality of the system.


2003 ◽  
Vol 68 (5) ◽  
Author(s):  
C. Pappas ◽  
F. Mezei ◽  
G. Ehlers ◽  
P. Manuel ◽  
I. A. Campbell
Keyword(s):  

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1669-1678 ◽  
Author(s):  
MAZHAR U. RANA ◽  
TAHIR ABBAS ◽  
M. ASHRAF CHAUDHRY

The magnetic susceptibility of MnO.Al2O3.SiO2 spin glasses has been measured over a temperature range of 1.5–150 K using a low-field ac mutual inductance technique. The measuring frequency was 250 Hz with a field of 417 mOe (peak). The Mn concentration varied from 6 to 19 atomic percent (at %). At temperatures above 70 K, the susceptibilities follow a Curie-Wiess behavior with a negative Curie temperature and a Bohr magneton number corresponding nearly to the free ion value of Mn. However, below 70 K all glass samples show strong deviation from the Curie-Wiess behavior (a decrease in 1/χ), culminating in spin glass susceptibility maxima at liquid helium temperature for Mn concentration above 9 at %. These results suggest the formation of antiferromagnetic cluster which grows in size with decreasing temperature and becomes infinitely large as the spin glass freezing temperature is approached.


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