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Pregled bibliografske jedinice broj: 271693

Thermal relaxation of magnetic clusters magnetization in Hf_{;57};Fe_{;43}; amorphous alloy


Pajić, Damir; Zadro, Krešo
Thermal relaxation of magnetic clusters magnetization in Hf_{;57};Fe_{;43}; amorphous alloy // Gordon research conference on magnetic nanostructures
Oxford, Ujedinjeno Kraljevstvo, 2006. (poster, međunarodna recenzija, neobjavljeni rad, ostalo)


Naslov
Thermal relaxation of magnetic clusters magnetization in Hf_{;57};Fe_{;43}; amorphous alloy

Autori
Pajić, Damir ; Zadro, Krešo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, neobjavljeni rad, ostalo

Skup
Gordon research conference on magnetic nanostructures

Mjesto i datum
Oxford, Ujedinjeno Kraljevstvo, 27.08.-01.09.2006

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Hf-Fe; magnetic clusters; thermal relaxation; amorphous alloy

Sažetak
In binary magnetic/nonmagnetic alloy Hf_{; ; 57}; ; Fe_{; ; 43}; ; the concentration of iron is just below the critical concentration for the onset of long range magnetic order in amorphous Hf_{; ; 100-x}; ; Fe_{; ; x}; ; system. Therefore, the magnetic clusters in a non-magnetic matrix are expected. Detailed measurements of magnetic hysteresis loops, temperature dependences of magnetization and relaxation of magnetization point to the superparamagnetic behaviour of clusters. When the thermal energy is lower than the magnetic anisotropy barrier, the magnetic moment of clusters stays blocked on one side of the barrier. Then the magnetic hysteresis appears because of slow relaxation which depends on applied magnetic field. Above the blocking temperature, the magnetic moment fluctuates over the barrier and there is no hysteresis. The magnetic behaviour is similar to random magnets and to ensemble of magnetic particles, and the measured properties are explained by existing models. Analysing the relaxation curves and using the model of thermal activation over the anisotropy barrier, the distribution of magnetic moments over the barriers is obtained. Knowing the anisotropy density, the characteristic size of clusters of 3-6nm follows. Hysteresis loops do not show exchange bias and surface disorder on clusters. The memory effects were not observed, too. The interaction of clusters with matrix or between clusters is not detected. Hence, this alloy is good candidate for magnetization tunneling investigation which should occur below 0.1K.

Izvorni jezik
Engleski

Znanstvena područja
Fizika



POVEZANOST RADA


Projekt / tema
0119258

Ustanove
Prirodoslovno-matematički fakultet, Zagreb

Autor s matičnim brojem:
Damir Pajić, (234522)
Krešo Zadro, (74153)