Vortex polarity switching in magnets with surface anisotropy

Vortex core reversal in magnetic particle is essentially influenced by a surface anisotropy. Under the action of a perpendicular static magnetic field the vortex core undergoes a shape deformation of pillow- or barrel-shaped type, depending on the type of the surface anisotropy. This deformation plays a key point in the…

Continue reading

Curvature effects in statics and dynamics of low dimensional magnets

Nowadays there is a growing interest in studying of topological structures in curved magnetic objects such as magnetic nanowires and nanoshells. We develop an approach to treat magnetic energy of a ferromagnet for arbitrary curved wires and shells on the assumption that the anisotropy contribution greatly exceeds the dipolar and…

Continue reading

Curvature Effects in Thin Magnetic Shells

The submbicron-scaled magnetism of solid state is a rapidly developing research area with a promising applied potential. Nanomagnets are often considered as elements of fast nonvolatile memory devices of high density. Up to now the theoretical study in this direction was restricted mostly by planar structures. In the current research…

Continue reading

OOMMF Utilities 1.0

Object Oriented Micromagnetic Framework (OOMMF) is free, portable, extensible public domain micromagnetic program and associated tools, which was developed at the National Institute of Standards and Technology (NIST). OOMMF is very powerful and useful tool which can be thinly configured for different micromagnetic studies, but at the same time, it…

Continue reading

Periodic magnetic structures generated by spin-polarized currents in nanostripes

We investigated the influence of a spin-polarized current on long ferromagnetic nanostripes. The magnetization behavior is analyzed for all range of the applied currents, up to the saturation. It is shown that the saturation current is a nonmonotonic function of the stripe width. For a stripe width increasing it approaches…

Continue reading

Regular and chaotic vortex core reversal by a resonant perpendicular magnetic field

We predict the regular and chaotic dynamics of the vortex polarity under the action of perpendicular ac magnetic field and propose a simple analytical description in terms of a reduced vortex core model. Phys. Rev. B, 88, 014432 (2013), 10.1103/PhysRevB.88.014432, PDF.

Continue reading

How to save intermediate result of calculations in Mathematica

Sometimes, one needs to make long-time pleriminary calculations in Mathematica to obtain expressions for further work. It is not convenien to make them every time when notebook opens again. An easy (but may be machine-dependent) way is to use DumpSave function. How it works. For example, we have a few…

Continue reading

Семінар «Спіновий струм і солітони в антиферомагнетиках»

У понеділок, 29 травня, в 11:00 відбудеться семінар на тему «Спіновий струм і солітони в антиферомагнетиках», доповідач Олександр Васильович Пилиповський. Місце проведення: Інститут теоретичної фізики імені Боголюбова. Значна кількість штучних і природних антиферомагнетиків, а також високі значення власних частот, які сягають ТГц, привертають значну увагу до їх експериментального і теоретичного дослідження. На…

Continue reading

Семинар «Магнитоэлектрические эффекты в композитных мультиферроиках»

15 апреля (понедельник) в Институте теоретической физики им. Боголюбова состоится семинар «Магнитоэлектрические эффекты в композитных мультиферроиках». Докладчик: Максим Александрович Попов, к.ф.-м.н., сотрудник Киевского национального университета имени Тараса Шевченка. Начало в 11:00, аудитория №322. Аннотация: Зависляк И.В., д.ф.-м.н., проф., Сохацкий В.П., к.ф.-м.н., доц., Попов М.А., к.ф.-м.н., м.н.с. Дан обзор магнитоэлектрических явлений…

Continue reading

Nmag console commands in a nutshell

Nmag is a python-based micromagnetic simulator for finite elements mesh. First we add the path and one alias for a comfort work to our bashrc from <nsim>/bin directory: echo "export PATH=\$PATH:`pwd`" >> ~/.bashrc echo "alias nmeshimportg='`pwd`/nmesimport –gmsh'" >> ~/.bashrc Convert the mesh in Version ASCII v2.x format to Version 1:…

Continue reading