The Landau–Lifshitz equation in atomistic models

The Landau–Lifshitz (LL) equation, originally proposed at the macrospin level, is increasingly used in Atomistic Spin Dynamic (ASD) models. These models are based on a spin Hamiltonian featuring atomic spins of fixed length, with the exchange introduced using the Heisenberg formalism. ASD models are proving a powerful approach to the fundamental understanding of ultrafast magnetization dynamics, including the prediction of the thermally induced magnetization switching phenomenon in which the magnetization is reversed using an ultrafast laser pulse in the absence of an externally applied field. This paper outlines the ASD model approach and considers the role and limitations of the LL equation in this context

Peculiarities of the stochastic motion in antiferromagnetic nanoparticles

Antiferromagnetic (AFM) materials are widely used in spintronic devices as passive elements (for stabilization of ferromangetic layers) and as active elements (for information coding). In both cases switching between the different AFM states depends in a great extent from the environmental noise. In the present paper we derive the stochastic Langevin equations for an AFM vector and corresponding Fokker-Planck equation for distribution function in the phase space of generalised coordinate and momentum. Thermal noise is modeled by a random delta-correlated magnetic field that interacts with the dynamic magnetisation of AFM particle. We analyse in details a particular case of the collinear compensated AFM in the presence of spin-polarised current. The energy distribution function for normal modes in the vicinity of two equilibrium states (static and stationary) in sub- and super-critical regimes is found. It is shown that the noise-induced dynamics of AFM vector has pecuilarities compared to that of magnetisation vector in ferromagnets.Comment: Submitted to EPJ ST, presented at the 4-th Conference on Statistical Physics, Lviv, Ukraine, 201

Papaya Ringspot Virus (PRV): A Serious Disease of Papaya

Short publication describing symptoms and control of papaya ringspot disease

Ultrafast thermally induced magnetic switching in synthetic ferrimagnets

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Perpendicular anisotropy L 10 -FePt based pseudo spin valve with Ag spacer layer

10.1063/1.3571450Applied Physics Letters9813-APPL

Muhasebede yabancı para birimi cinsinden işlemler ve muhasebeleştirilmesi

Yabancı para birimi cinsinden işlemlerin muhasebeleştirilmesi. Günümüzde dünyadaki gelişmelere paralel olarak ekonomik yaşamın hızla değişmesi, ekonomik kriz ve konjonktürel dalgalanmalar, özellikle kronik ve yüksek halde seyreden enflasyon, işletmeler için zor koşullar ve olumsuzluklar meydana getirmektedir.Bu iktisadi olayların cereyan etmesi; işletmelerde, aktifte kayıtlı iktisadi kıymetler, bilanço kalemleri, mali tablolar, yatırım plan ve projeleri üzerinde ve kar veya zararın oluşmasında belirleyici bir etken olmaktadır. Bu nedenle vergi reformları dizgesi içinde yer alan yeni reform yasası ile Türkiye'de yüz milyon doların üzerinde yatırım yapan yabancı yatırımcılara, yabancı para cincinden muhasebe tutma ayrıcalığının verilmesinin değişik boyutları bulunmaktadır.Üstelik de daha istikrarlı olacağı varsayımı ile para biriminin değiştirildiği bir dönemde.Bunun yanı sıra enflasyon muhasebesinin uygulanmaya başladığı bir dönemde.Bununla beraber, 6 sıfırın atılması da yabancı para için başka bir gelişme olarak gözükmektedir. Günümüzde yabancı para birimi cinsinden işlemler ve muhasebeleştirilmesi, üzerinde önemle durulmaktadır.Sonuç olarak, yabancı para cinsinden işlemler yeni bir boyutla incelenmiştir

Micromagnetic modelling of L10-FePt/Ag/L10-FePt pseudo spin valves

10.1063/1.3653290Applied Physics Letters9916-APPL

Atomistic modeling of the interlayer coupling behavior in perpendicularly magnetized L10-FePt/Ag/L10-FePt pseudo spin valves

10.1109/TMAG.2011.2147765IEEE Transactions on Magnetics47102646-2648IEMG

The Effect of Interstitial Nitrogen Addition on the Structural Properties of Supercells of NdFe12-xTix x

We investigated the effect of nitrogenation on $3 \times 3 \times 2$ supercell structures of NdFe 12-x Ti x from $x = 0.028$ to $x = 1.56$ (~0.2Ti at. % to ~12Ti at. %). We used the molecular dynamics and Boltzmann probabilities to permeate titanium into NdFe 12-x Ti x across the investigated range, before nitrogenating the minimum energy structures that resulted at each permutation step. By comparison of the nitrogenated and base structures, we found that the cohesive energy gains caused by nitrogenation are mainly due to a large asymmetry introduced into the $c$ lattice parameter and the efficacy of nitrogenation decreases with increasing titanium at. %

Engineering Ultrafast Magnetism

We employ time-resolved X-ray magnetic circular dichroism with fs time resolution to investigate the ultrafast, laser-driven dynamics of multi-sublattice materials, with both ferromagnetic and antiferromagnetic coupling. These measurements provide evidence for a demagnetization time that scales with the elemental magnetic moment and varies with the exchange interaction symmetry