Presenting our work at MMM 2016

We recently presented our work at the 61st Annual Conference on Magnetism and Magnetic Materials in New Orleans LA.  Dr. Tim Mercer is shown here at the Wednesday poster session discussing our findings on “Mesoporous Nanoparticle Supported Liposomes for Magnetic Hyperthermia Triggered Drug Delivery”

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This entry was posted on December 8, 2016. 1 Comment

Paper published on the interaction of magnetisation and heat dynamics in pulsed domain wall movement

The following paper has been published in the Journal of Applied Physics:

Interaction of magnetization and heat dynamics for pulsed domain wall movement with Joule heating

http://dx.doi.org/10.1063/1.4966607

Abstract

Pulsed domain wall movement is studied here in Ni80Fe20 nanowires on SiO2 , using a fully integrated electrostatic, thermoelectric, and micromagnetics solver based on the Landau-Lifshitz-Bloch equation, including Joule heating, anisotropic magneto-resistance, and Oersted field contributions. During the applied pulse, the anisotropic magneto-resistance of the domain wall generates a dynamic heat gradient, which increases the current-driven velocity by up to 15%. Using a temperature-dependent conductivity, significant differences are found between the constant voltage-pulsed and constant current-pulsed domain wall movement: constant voltage pulses are shown to be more efficient at displacing domain walls whilst minimizing the increase in temperature , with the total domain wall displacement achieved over a fixed pulse duration having a maximum with respect to the driving pulse strength.

Presenting our work at JEMS 2016

The Joint European Magnetics Symposia (JEMS) 2016 is in full swing.  Glasgow is an interesting city that gives visitors a warm and friendly welcome.  On Monday Dr. Serban Lepadatu presented work on the effects of edge and surface roughness in ferromagnetic nanowires (Poster PS.1.082) and on Tuesday Mr. Steven Bourn gave a talk on our multi-ferroic project concerning the effects of anisotropy in the magnetic layer on the Magneto-Coupling effect (Sumposium “Perovskites, multiferroics, artificial/composite multiferroics)

 

Presentation of our latest Multi-Ferroic Work

“The Effects of Multiple Anisotropy axes on Magneto-Electric Coupling in Multiferroic Composites”

Yesterday was our slot (AP-03) for the morning presentation of our latest work on multi-ferroic composites.  The photo shows Tim Mercer at the end of the session stood by his poster.  The poster generated a lot of interest and forms the main part of Steven Bourn’s PhD project.

The 13 Joint MMM-Intermag Conference is in San Diego, CA and is amongst the biggest and most widely accepted forum for bringing together researchers from all over the world to present asnd discuss their research on all aspects of magnetism and magnetic materials

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This entry was posted on January 13, 2016. 2 Comments

Welcome to San Diego for the 13th Joint MMM-Intermag Conference

The conference has kicked-off in fine style with the tradiional BierStube (and what a fine tradtion it is).

Tomorrow I will be presenting the work from our Multi-ferroic project (the postgraduate PhD student on this project is Mr Steven Bourn) in the morning poster session.  In the meantime, a few images from near the hotel:

 

Paper describing new model for determining the effect of roughness in magnetic nano-structures accepted for publication

The following paper has been accepted for publication in the Journal of Applied Physics:

http://arxiv.org/abs/1508.04391

S. Lepadatu, “Effective Field Model of Roughness in Magnetic Nano-structures”, Journal of Applied Physics (In Press).

Abstract: An effective field model is introduced here within the micromagnetics formulation, to study roughness in magnetic structures, by considering sub-exchange length roughness levels as a perturbation on a smooth structure. This allows the roughness contribution to be separated, which is found to give rise to an effective configurational anisotropy for both edge and surface roughness, and accurately model its effects with fine control over the roughness depth without the explicit need to refine the computational cellsize to accommodate the roughness profile. The model is validated by comparisons with directly roughened structures for a series of magnetization switching and domain wall mobility simulations and found to be in excellent agreement for roughness levels up to the exchange length. The model is further applied to vortex domain wall mobility simulations with surface roughness, which is shown to significantly modify domain wall movement and result in dynamic pinning and stochastic creep effects.

Paper published on a method to characterise anisotropy axes in soft magnetic materials

The group has published the following paper in IEEE Transaction on Magnetics:

http://dx.doi.org/10.1109/TMAG.2015.2435365

S. Bourn, T. Mercer, P.R. Bissell and M. Vopson, “Development of a Method to Identify In-Plane Anisotropy Axes in Soft Magnetic Materials Using a Standard Vibrating Sample Magnetometer”, IEEE Trans. Magn., 51, (2015) (600604)

Abstract:   A method of identifying in-plane anisotropy axes in soft magnetic materials has been developed using an in-field-only measurement technique. The method is based on an extended bi-axial Vibrating Sample Magnetometer (VSM) technique that simulates the torque on a sample; giving rise to equivalent torque curves that are comparable with those determined directly using a torque magnetometer. Testing of the new methodology was carried out on magnetically soft and multi-axial nickel ferrite textured films deposited with various crystal orientations. The results compare well with the accepted bi-axial VSM technique, identifying the same in-plane anisotropy directions and relative easy and hard axes from the in-field measurement alone. This means that these characteristics could be determined using a standard VSM measuring magnetization in the field direction as long as it is fitted with a rotating sample stage.