Estimation of magnetic anisotropy constant of magnetic nanoparticles

2020 ◽  
Author(s):  
Navneet Kaur ◽  
S. D. Tiwari
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Anisotropy ◽  
Anisotropy Constant ◽  
Magnetic Anisotropy Constant

scholarly journals Nanoparticle Size Threshold for Magnetic Agglomeration and Associated Hyperthermia Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2786
Author(s):  
David Serantes ◽  
Daniel Baldomir
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Anisotropy ◽  
Magnetic Dipole ◽  
Anisotropy Constant ◽  
K Value ◽  
Threshold Size ◽  
Magnetic Anisotropy Constant ◽  
Agglomeration Process ◽  
Size Threshold

The likelihood of magnetic nanoparticles to agglomerate is usually estimated through the ratio between magnetic dipole-dipole and thermal energies, thus neglecting the fact that, depending on the magnitude of the magnetic anisotropy constant (K), the particle moment may fluctuate internally and thus undermine the agglomeration process. Based on the comparison between the involved timescales, we study in this work how the threshold size for magnetic agglomeration (daggl) varies depending on the K value. Our results suggest that small variations in K-due to, e.g., shape contribution, might shift daggl by a few nm. A comparison with the usual superparamagnetism estimation is provided, as well as with the energy competition approach. In addition, based on the key role of the anisotropy in the hyperthermia performance, we also analyse the associated heating capability, as non-agglomerated particles would be of high interest for the application.

Temperature Behavior of Magnetization in Multiphase Co-P Powders in Unsaturated Regime

2015 ◽  
Vol 233-234 ◽  
pp. 522-525
Author(s):  
Oksana Anatoljevna Li ◽  
Sergey Viktorovich Komogortsev ◽  
Rauf S. Iskhakov ◽  
Lidia Aleksandrovna Chekanova ◽  
Evgeniy V. Eremin
Keyword(s):  
Magnetic Anisotropy ◽  
Temperature Dependence ◽  
Spontaneous Magnetization ◽  
Anisotropy Constant ◽  
Surprising Result ◽  
Zero Temperature ◽  
Bloch Constant ◽  
Magnetic Anisotropy Constant ◽  
Fitting Parameters ◽  
Good Agreement

In this paper we have proposed a modified expression for the fitting M(T) data in Co-P powders with nanocorundum and nanodiamond precipitates. The expression for M(T) takes into account the effects from both thermal magnetic excitations – Bloch’s T 3/2 law and temperature dependence of the magnetic anisotropy. The fitting parameters are spontaneous magnetization at absolute zero temperature, Bloch constant and order of magnetic anisotropy constant. The obtained Bloch constant is in good agreement with literature data. The order of magnetic anisotropy constant is found to be about 3 that is surprising result and supposedly comes from multiphase nature of the investigated Co-P powder.

scholarly journals Влияние дисперсии магнитной анизотропии кластеров Ge-=SUB=-3-=/SUB=-Mn-=SUB=-5-=/SUB=- на температурные зависимости намагниченности тонких пленок Ge:Mn

2019 ◽  
Vol 45 (2) ◽  
pp. 36
Author(s):  
А.И. Дмитриев ◽  
М.С. Дмитриева ◽  
Г.Г. Зиборов
Keyword(s):  
Magnetic Field ◽  
Magnetic Anisotropy ◽  
Lognormal Distribution ◽  
Anisotropy Constant ◽  
Zero Field ◽  
Magnetization Curves ◽  
Magnetic Anisotropy Energy ◽  
Size Dependent ◽  
Magnetic Anisotropy Constant ◽  
Temperature Dependences

AbstractThe temperature dependences of magnetization M ( T ) of thin ion-implanted Ge:Mn (4 at % Mn) films containing Ge_3Mn_5 clusters were measured on samples cooled in the absence of magnetic field (zero field cooled, ZFC) and in a magnetic field of 10 kOe (field-cooled, FC). It has been established that the shape of ZFC–FC differential M ( T ) curves is determined by lognormal distribution of the size-dependent magnetic anisotropy energy of Ge_3Mn_5 clusters. Analysis of the observed ZFC–FC magnetization curves allowed the magnetic anisotropy dispersion (variance) and magnetic anisotropy constant to be estimated.

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