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Graduate Research Talk

Fri. Mar. 27 03:30 PM - Fri. Mar. 27 04:30 PM
Location: 330 Allen Bldg (UManitoba)

University of Manitoba Physics' Colloquium

"Graduate Research at the Frontiers of Physics and Astronomy"

Graduate Students in the Physics & Astronomy Department of the University of  Manitoba

Come out to support Taraneh Andalib! (UWinnipeg supervisors Jeff Martin & Russell Mammei)


1)  Bimu Yao

Title:  Quantifying the complex permittivity and permeability of magnetic nanoparticles

Abstract: The complex permittivity and permeability of superparamagnetic iron-oxide nanoparticles has been quantified using a circular waveguide assembly with a static magnetic field to align the nanoparticle’s magnetization. The high sensitivity of the measurement provides the precise resonant feature of nanoparticles. The complex permeability in the vicinity of ferromagnetic resonance (FMR) is in agreement with the nanoparticle’s measured magnetization via conventional magnetometry. A rigorous and self-consistent measure of complex permittivities and permeabilities of nanoparticles is crucial to ascertain accurately the dielectric behaviour as well as the frequency response of nanoparticle magnetization, necessary ingredients when designing and optimizing magnetic nanoparticles for biomedical applications.


2)  Taraneh Andalib

Title:  Magnetic Fields for neutron electric dipole moment measurement


Abstract:   Nonzero electric dipole moments exist if parity (P) and time-revesral (T) symmetries are violated. By CPT invariance, EDMS probe CP violation. The Sakharov criterias require CP-violation to create the observed baryon asymmetry in the universe. The scenario of electroweak baryogenesis requires additional sources of CP violation near the electroweak scale. Next generation neutron EDM experiments are sensetive to such sources. In our experiment, ultra cold neutrons (UCN) will be produced using a new source being constructed at TRIUMF (Canada's national laboratory of particle and nuclear physics) . UCN will be transported to a material bottle located inside parallel electric and magnetic fields. A very stable and homogeneous magnetic field (~1 Micro Tesla) will be produced by coils inside passive magnetic shields, in turn located within an active magnetic shielding system. The precision goal for this measurement is ~10^{-27} e.cm representing a factor 30 improvement over the previous best experiment. The experiment requires ~pT stability on the ~Micro Tesla magnetic field within the shields over hundreds of seconds and ~nT/m homogeneity. One avenue I am pursuing to address is to study the temperature dependence of the magnetic permeability of high-permeability magnetic materials using various techniques. The results aim at separating out one component of field internal to the passive magnetic shielding. I am also studying analytic and numerical calculations of magnetic field profiles for various coil designs, aimed at addressing the homogeneity requirements. The present status of those experiments and calculations will be presented.


3)  Jennifer West

Title: Nature's super-colliders: Supernova remnants and how they are connected to our Galaxy

Abstract:  Supernova explosions are some of the most significant and transformative events in our Universe. Understanding Supernova Remnants (SNRs), the leftover remains of these explosions, is fundamental to our understanding of the chemical enrichment and magnetism in galaxies, including our own Milky Way. We use current models of the Galactic magnetic field and electron density to simulate the emission from the SNRs as a function of their position in the Galaxy. We do this in an effort to understand the connection between SNRs and their environment and to investigate the relationship between the angle of the symmetry axis of the SNR and the Galactic Magnetic field. This relationship has implications for understanding the magnetic field geometry and cosmic ray electron distribution in SNRs, and possibly even a new method for determining or constraining the distances to SNRs.