Skip to main content Skip to navigation

Events in Physics

Show all calendar items

Barry Narod (Narod Geophysics/UBC)

- Export as iCalendar
Location: PS1.28

The origin of noise and of magnetic hysteresis in permalloy ring-core fluxgate sensors

6-81.3 Mo permalloy, developed in the 1960s for use in high performance ring-core fluxgate sensors, remains the state-of-the-art for permalloy-cored fluxgate magnetometers. The choices made at that time are reviewed in the context of what are now considered best practices for sensor design. The magnetic properties of 6-81.3, namely magnetocrystalline and magnetoelastic anisotropies and saturation induction are all optimum in the Fe-Ni-Mo system. Recent data suggest that the geometries of typical ring-cores are not optimum, and further suggest a direct relationship between magnetometer noise and domain wall energy. A model is presented for domain walls in magnetically soft, thin foil material, one that provides a basis for relating fluxgate noise power, domain wall energy and magnetostatic energy due to anisotropy. The model predicts the existence of a novel domain configuration for magnetic saturation that requires the presence of shallow, channel-like domains [channel domains], topologically distinct from typical thin foil stripe domains. Transitions between these two states require exothermic magnetic domain wall reconnections which can be identified with Barkhausen jumps, and are the basis for magnetometer noise. The channel domain concept also leads to explanations for remanence, for DC coercivity and for DC hysteresis in an otherwise ideal soft magnetic material. The open loop of DC hysteresis results from the continual cycling between ordinary stripe domain states and channel domain states.

Show all calendar items

Academic Leave Diary

Click here

 

Physics Days

Event listing

Research Group Events

Theory

CFSA

Astronomy

Particle Physics

Complexity

CSC

Condensed Matter Physics

.

Open Funder Deadlines


UKRI - Daphne Jackson Fellowship

Diamond Studentships 2024

.

UKRI Deadlines

Due to the implementation of a new UKRI funding system (TFS) there will be a fixed quarterly deadlines for some grants which would previously have been on open calls, this is to allow necessary system amendments and updates.

The first deadline after implementation will be 28th September 2023 and applies to those calls listed below:

EPSRC New Investigator Award

EPSRC Network Grant

EPSRC Post Doctoral Fellowship

EPSRC Open Fellowship

EPSRC Open Plus Fellowship

EPSRC Working with overseas scientists

EPSRC Standard research grant

EPSRC Discipline hopping in ICT

EPSRC Overseas travel grant