Kristal Alan Varlığında Nanoparçacığın Manyetik Özelliklerinin Büyüklüğe Bağlı Olarak İncelenmesi
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Tarih
2013
Yazarlar
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Yayıncı
Niğde Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tezde, kare ve altıgen örgüler üzerinde tanımlanan bilineer (J) ve kristal alan (D) etkile?meli spin-1 Ising modeli çekirdek-yüzey nanoparçacıkların manyetik özelliklerini incelemek amacıyla kullanıldı. Nanoparçacığın çekirdek (C), arayüzey (CS) ve yüzey (S) kesimlerindeki Ising spinleri çift yaklaşım yöntemiyle dahil edildi. Model Hamiltonyen ifadesi kullanılarak C, CS ve S kesimleri için bağ enerji parametreleri (Eij) tespit edildi ve bağ değişkenleri (Pij) için özuyumlu denklemler türetildi. Pij nin ve hal denkleminin (mıknatıslanma e?itliğinin) sayısal çözümünden nanoparçacığın sıcaklık ve yarıçap gelişimi farklı manyetik alan ve kristal alan değerleri için çalışıldı. Kare ve altıgen örgülü homojen ve kompozit nanoparçacık için spin valf davranışının kaynağı farklı sıcaklık ve manyetik alanda gözlendi
In this thesis, spin-1 Ising model with bilinear (J) and crystal field (D) interactions on square and hexagonal lattices is used to investigate the magnetic properties of coresurface nanoparticles. The Ising spins of the nanoparticles in core (C), core-surface (CS), and surface (S) parts were incorporated with the pair approximation method. Using the model Hamiltonian expression, the bond energy parameters (Eij) forC ,CS and S parts were determined and a set of self-consistent equations for the bond variables (Pij) were derived. From the numerical solutions of Pij and the equation of state (or magnetization equation), the temperature and diameter evolutions of nanoparticles were studied for different values of magnetic and crystal field. The origin of the spin valve behavior for homogeneous and composite nanoparticles with square and hexagonal lattice structures has been observed at various temperatures and magnetic fields …
In this thesis, spin-1 Ising model with bilinear (J) and crystal field (D) interactions on square and hexagonal lattices is used to investigate the magnetic properties of coresurface nanoparticles. The Ising spins of the nanoparticles in core (C), core-surface (CS), and surface (S) parts were incorporated with the pair approximation method. Using the model Hamiltonian expression, the bond energy parameters (Eij) forC ,CS and S parts were determined and a set of self-consistent equations for the bond variables (Pij) were derived. From the numerical solutions of Pij and the equation of state (or magnetization equation), the temperature and diameter evolutions of nanoparticles were studied for different values of magnetic and crystal field. The origin of the spin valve behavior for homogeneous and composite nanoparticles with square and hexagonal lattice structures has been observed at various temperatures and magnetic fields …
Açıklama
Anahtar Kelimeler
Manyetik Nanoparçacıklar, İsing Modeli, Çift Yaklaşım Modeli, Kristal Alan Etkileşmesi
