Publications associées à Magnetoresistance measurement of tailored Permalloy nanocontacts

Magnetic structure of the topological semimetal Co3Sn2S2

Henrik Moodysson Rønnow, Ivica Zivkovic, Jian Rui Soh

Co3Sn2S2 has recently been predicted to be a Weyl semimetal in which magnetic order is key to its behavior as a topological material. Here, we report unpolarized neutron diffraction and spherical neutron polarimetry measurements, supported by magnetization ...

AMER PHYSICAL SOC2022

Challenges and Applications to Operando and In Situ TEM Imaging and Spectroscopic Capabilities in a Cryogenic Temperature Range

Martial Duchamp, Vasiliki Tileli, Reinis Ignatans

In this Account, we describe the challenges and promising applications of transmission electron microscopy (TEM) imaging and spectroscopy at cryogenic temperatures. Our work focuses on two areas of application: the delay of electron-beam-induced degradatio ...

AMER CHEMICAL SOC2021

Individual Barkhausen Pulses of Ferroelastic Nanodomains

Dragan Damjanovic, Vasiliki Tileli, Reinis Ignatans

Ferroelectric materials, upon electric field biasing, display polarization discontinuities known as Barkhausen jumps, a subclass of a more general phenomenon known as crackling noise. Herein, we follow at the nanoscale the motion of 90 degree needle domain ...

2021

Frequency-dependent decoupling of domain-wall motion and lattice strain in bismuth ferrite

Dragan Damjanovic

Dynamics of domain walls are among the main features that control strain mechanisms in ferroic materials. Here, we demonstrate that the domain-wall-controlled piezoelectric behaviour in multiferroic BiFeO3 is distinct from that reported in classical ferroe ...

Nature Research2018

Controlling the Topological Sector of Magnetic Solitons in Exfoliated Cr1/3NbS2 Crystals

Frédéric Mila, Fengping Li, Natalia Chepiga

We investigate manifestations of topological order in monoaxial helimagnet Cr1/3NbS2 by performing transport measurements on ultrathin crystals. Upon sweeping the magnetic field perpendicularly to the helical axis, crystals thicker than one helix pitch (48 ...

2017

Dynamical Defects in Rotating Magnetic Skyrmion Lattices

Helmuth Berger

The chiral magnet Cu2OSeO3 hosts a Skyrmion lattice that may be equivalently described as a superposition of plane waves or a lattice of particlelike topological objects. A thermal gradient may break up the Skyrmion lattice and induce rotating domains, rai ...

Amer Physical Soc2017

Magnetic properties of surface-adsorbed single rare earth atoms, molecules, and atomic scale clusters

Aparajita Singha

This thesis presents combined experimental and theoretical investigations of nanoscale, surface-supported magnets based on rare earths (RE) to understand and control the magnetic properties down to the scale of single atoms. We present the effects of adato ...

EPFL2017

Identification of microscopic domain wall motion from temperature dependence of nonlinear dielectric response

Pavel Mokry, Tomas Sluka

It is known that the permittivity of ferroelectric polydomain films and single crystals in weak electric fields is strongly enhanced by the reversible movement of pinned domain walls. Two mechanisms of the movement exist: first, the bending of free segment ...

Amer Inst Physics2017

Frobenius techniques in birational geometry

Zsolt Patakfalvi

This is a survey for the 2015 AMS Summer Institute on Algebraic Geometry about the Frobenius type techniques recently used extensively in positive characteristic algebraic geometry. We first explain the basic ideas through simple versions of the fundamenta ...

2017

Visualisation of magnetic domain structures and magnetisation processes in Goss-oriented, high permeability steels using neutron grating interferometry

Benedikt Karl-Josef Gerhard Betz

Industrial transformers cores are built from stacked sheets of an iron silicon alloy, called laminations. The magnetic domain structures of these highly anisotropic electrical steels with a sharp (110)[001]-texture, the so-called Gosstexture, determines th ...

EPFL2016

Experimental and first-principles study of point defects, domain walls, and point-defect/domain-wall interactions in ferroelectric oxides

Anand Chandrasekaran

Ferroelectric oxides, such as lead zirconate titanate, have proved invaluable due to their excellent dielectric and piezoelectric properties. These classes of materials possess a large electric polarization below the Curie temperature. Regions of the cryst ...

EPFL2016

Torque magnetometry study of magnetically ordered state and spin reorientation in the quasi-one-dimensional S=1/2 Heisenberg antiferromagnet CuSb2O6

Helmuth Berger

The antiferromagnetically ordered state of the monoclinic quasi-one-dimensional S = 1/2 Heisenberg antiferromagnet CuSb2O6 was studied combining torque magnetometry with a phenomenological approach to magnetic anisotropy. This system is known to have a num ...

Amer Physical Soc2015

Growth and Magnetism of Nanostructures Investigated by STM, MOKE, and XMCD

Alberto Cavallin

This thesis presents our studies on nanostructures growth and magnetism, mainly based on scanning tunneling microscopy (STM), magneto-optical Kerr effect (MOKE), and x-ray magnetic circular dichroism (XMCD) measurements. In most of these experiments, nanos ...

EPFL2013

Magnetic domain wall propagation under ferroelectric control

Nava Setter, Igor Stolichnov, Harry Joseph Trodahl, Evgeny Mikheev, Sebastian Riester

Control of magnetic domain walls (DWs) and their propagation is among the most promising development directions for future information-storage devices. The well-established tools for such manipulation are the spin-torque transfer from electrical currents a ...

American Physical Society2012

Ultrafast optical demagnetization manipulates nanoscale spin structure in domain walls

During ultrafast demagnetization of a magnetically ordered solid, angular momentum has to be transferred between the spins, electrons, and phonons in the system on femto-and picosecond timescales. Although the intrinsic spin-transfer mechanisms are intense ...

Nature Publishing Group2012

Domain wall configuration and magneto-transport properties in dual spin-valve with nanoconstriction

Santiago Serrano Guisan

We investigated the effect of external field on magneto-transport properties of synthetic antiferromagnet dual spin-valve with nanoconstriction with focus on domain wall (DW) configuration and magnetization reversal process. As magnetic field rotated from ...

AIP American Institute of Physics2012

Spin configurations in Co2FeAl0.4Si0.6 Heusler alloy thin film elements

André Bisig

We determine experimentally the spin structure of half-metallic Co2FeAl0.4Si0.6 Heusler alloy elements using magnetic microscopy. Following magnetic saturation, the dominant magnetic states consist of quasi-uniform configurations, where a strong influence ...

AIP American Institute of Physics2011

Broadband Dielectric Response in Hard and Soft PZT : Understanding Softening and Hardening Mechanisms

Li Jin

Lead zirconate titanate (Pb(Zr1-xTix)O3 or PZT) ferroelectric ceramics have been widely used in transducers, actuators, and sensors, since they posses high dielectric and piezoelectric properties with a relatively high temperature of operation. Commerciall ...

EPFL2011

Neutron Decoherence Imaging for Visualizing Bulk Magnetic Domain Structures

Martin Dierolf, Christian David

Here we introduce a novel neutron imaging method, which is based on the effect that the spatial coherence of the neutron wave front can be changed through small-angle scattering of neutrons at magnetic domain walls in the specimen. We show that the techniq ...

2008

Fabrication of curved-line nanostructures on membranes for transmission electron microscopy investigations of domain walls

Robin Schäublin, Christian David

We have fabricated curved-line ferromagnetic nanostructures on membranes for transmission electron microscopy investigations of the equilibrium magnetic spin configurations. The magnetic elements were fabricated using electron-beam lithography and a lift-o ...

2006