Frustrated states of the spin-glass type in diluted ferrimagnetic oxides

2005 ◽  
Vol 31 (5) ◽  
pp. 389-401 ◽  
Author(s):  
N. N. Efimova
Keyword(s):  
ChemInform ◽  
2010 ◽  
Vol 41 (36) ◽  
pp. no-no
Author(s):  
E. E. Tareyeva ◽  
T. I. Schelkacheva ◽  
N. M. Chtchelkatchev
Keyword(s):  

1990 ◽  
Vol 87 (1) ◽  
pp. 237-240 ◽  
Author(s):  
Frank J. Berry ◽  
Megan I. Sarson ◽  
Javier Tejada ◽  
Amilcar Labarta ◽  
Raul Rodriguez ◽  
...  

2019 ◽  
Vol 5 (7) ◽  
pp. eaav3842 ◽  
Author(s):  
Yipei Guo ◽  
Marija Vucelja ◽  
Ariel Amir

Adaptation, where a population evolves increasing fitness in a fixed environment, is typically thought of as a hill-climbing process on a fitness landscape. With a finite genome, such a process eventually leads the population to a fitness peak, at which point fitness can no longer increase through individual beneficial mutations. Instead, the ruggedness of typical landscapes due to epistasis between genes or DNA sites suggests that the accumulation of multiple mutations (via a process known as stochastic tunneling) can allow a population to continue increasing in fitness. However, it is not clear how such a phenomenon would affect long-term fitness evolution. By using a spin-glass type model for the fitness function that takes into account microscopic epistasis, we find that hopping between metastable states can mechanistically and robustly give rise to a slow, logarithmic average fitness trajectory.


2012 ◽  
Vol 560-561 ◽  
pp. 766-770 ◽  
Author(s):  
Yu Deng ◽  
Di Wu ◽  
You Wei Du

By hydrothermal methods single-crystalline BiFeO3 (BFO) nanorods with diameters of 15-40nm and lengths of 100-400nm were synthesized. The rhombohedra phased nanorods grow along the [110] direction. The nanorods show weak ferromagnetism at room temperature and enhanced spin-glass type magnetism at low temperature. Around 100K, a strong spin-two-phonon coupling has been detected, confirming the spin-glass freezing behaviors. With emphasis on the size and morphology, the enhanced magnetism and the spin-glass freezing of the BFO nanorods have been discussed.


2009 ◽  
Vol 160 (2) ◽  
pp. 1190-1202 ◽  
Author(s):  
E. E. Tareyeva ◽  
T. I. Schelkacheva ◽  
N. M. Chtchelkatchev
Keyword(s):  

2013 ◽  
Vol 202 ◽  
pp. 155-160
Author(s):  
Kalpesh H. Jani ◽  
Amish G. Joshi ◽  
H.H. Joshi

The spinel ferrite system CoZnzGezCrx-zFe2-x-zO4with z= x2;x = 0.60, 0.65 and 0.70 was studied by Mà T (ZFC-FC) DC magnetization at low and high fields in the temperature range 5K to 300K, MàH measurements with high field up to 55 kOe at 15K temperature and low field AC susceptibility in temperature range 77K to 300K. We observe thermo-magnetic irreversibility (TMI) in MàT study, high field slope with high coercivity in MàH study. The composition x = 0.70 shows constricted hysterisis loop at 15K. We observed a cusp at transition temperature in AC susceptibility measurements. We have shown that the features observed in all these measurements are adequately explained using domain wall dynamics and inherent magneto-crystalline anisotropy without invoking the concept of cluster spin-glass type ordering in x = 0.60 and x = 0.65 in temperature range 5K to 300K. The sample x= 0.70, however showed signatures of cluster spin-glass type of ordering at low temperature as revealed in non-Brillouin type shape of low field FC curves in MàT DC magnetization and constricted hysterisis loop at 15K temperature.


1970 ◽  
Vol 32 (2) ◽  
Author(s):  
AK Das ◽  
AKM Zakaria ◽  
I Kamal

The magnetic properties of polycrystalline CuMPt6 (M= Ti, V, Cr, Mn, Fe, Co and Ni) ternary alloys were studied by Superconducting Quantum Interference Device (SQUID) over the temperature range 4-300 K. Magnetization measurements revealed that the compounds containing M=Ti, V and Ni are paramagnetic. A spin glass type magnetic behavior appeared in the compounds with M= Cr and Mn in their annealed state and the corresponding temperatures for freezing the magnetic moments were Tg= 15 and 40 K, respectively. Positive values of the paramagnetic Curie temperature (Q) indicated that the ferromagnetic interaction is dominant in these spin-glass compounds. The compounds with M= Fe and Co showed ferromagnetic behavior having Curie temperatures (TC) = 230, and 190 K, respectively. Hysteresis study showed that the alloy with M=Co was magnetically softer than that with M=Fe. Keywords: CuMPt6 ternary alloys, Magnetic behavior, Effective magnetic moments (Peff), Spin glass type. doi: 10.3329/jbas.v32i2.2428 Journal of Bangladesh Academy of Sciences Vol.32(2) 2008 218-225


2015 ◽  
Vol 92 (21) ◽  
Author(s):  
S. Chowki ◽  
S. Rayaprol ◽  
A. Mukhopadhyay ◽  
N. Mohapatra

Sign in / Sign up

Export Citation Format

Share Document