Publications related to Magnetic refrigeration

Magnetism of Single Surface Adsorbed Atoms Studied with Radio-Frequency STM

This thesis investigates the magnetic properties of single atoms and molecules adsorbed on thin magnesium oxide decoupling layers, grown on a silver single crystal. To address these systems experimentally, we use a low temperature scanning tunneling micros ...

EPFL2024

The Impact of Lattice Distortions on the Magnetic Stability of Single Atoms: Dy and Ho on BaO(100)

Harald Brune, Stefano Rusponi, Marina Pivetta, Darius Constantin Merk, Boris Sorokin, Sébastien Reynaud

X-ray magnetic circular dichroism, atomic multiplet simulations, and density functional theory calculations are employed to identify criteria for the optimum combination of supporting alkaline earth oxide and adsorption site maximizing the spin lifetimes o ...

WILEY-V C H VERLAG GMBH2023

Increasing Magnetic Anisotropy in Bimetallic Nanoislands Grown on fcc(111) Metal Surfaces

Harald Brune, Stefano Rusponi, Sergio Vlaic, Dimitrios Mousadakos

The magnetic properties and the atomic scale morphology of bimetallic two-dimensional nanoislands, epitaxially grown on fcc(111) metal surfaces, have been studied by means of Magneto-Optical Kerr Effect and Scanning Tunneling Microscopy. We investigate the ...

MDPI2022

Influence of static correlation on the magnon dynamics of an itinerant ferromagnet with competing exchange interactions: First-principles study of MnBi

Henrik Moodysson Rønnow, Thorbjørn Skovhus

We present first-principles calculations of the dynamic susceptibility in strained and doped ferromagnetic MnBi using time-dependent density functional theory. In spite of being a metal, MnBi exhibits signatures of strong correlation and a proper descripti ...

AMER PHYSICAL SOC2022

Universal Aspects of Metamagnetic Transitions in Frustrated Ising Chains

Nagabhushan Ganesh Hegde

The study of magnetic frustration has been interesting due to the variety of magnetic ordering observed at low temperatures. At these temperatures thermal fluctuations become redundant and quantum fluctuations play a significant role in the determining the ...

EPFL2021

Magnetic 2D materials and heterostructures

Marco Gibertini

The family of two-dimensional (2D) materials grows day by day, hugely expanding the scope of possible phenomena to be explored in two dimensions, as well as the possible van der Waals (vdW) heterostructures that one can create. Such 2D materials currently ...

Nature Publishing Group2019

New Insights into the Verwey Transition in Magnetite

Simone Borroni

Magnetite (Fe

_3

O

_4

) is the first magnetic material discovered by mankind. Despite thousands of years of applications, from the magnetic compass to data storage, and decades of basic research, it remains among the most fascinating materials for physicis ...

EPFL2018

J1−J2 square-lattice Heisenberg antiferromagnets with 4d1 spins: AMoOPO4Cl (A=K,Rb)

Henrik Moodysson Rønnow, Peter Babkevich

Magnetic properties of AMoOPO4Cl (A=K,Rb) with Mo5+ ions in the 4d1 electronic configuration are investigated by magnetization, heat capacity, and nuclear magnetic resonance (NMR) measurements on single crystals, combined with powder neutron diffraction ex ...

2017

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

Synthesis and Physical Properties of 3d, 4d and 5d Transition Metal Compounds

Lin Yang

In this thesis I study the synthesis and basic physical properties characterization on 3

d

, 4

d

and 5

d

transition metal compounds. Great success has been obtained in 3

d

transition metal compounds, in which the electric states are well localized due t ...

EPFL2017

Spin and orbital disordering by hole doping in Pr1-xCaxVO3

Philip Pattison

High-resolution powder x-ray diffraction and single-crystal neutron diffraction were used to investigate the crystal structure and magnetic ordering of the compound Pr1-xCax VO3 (0

Amer Physical Soc2016

Magnetic anisotropy in the frustrated spin-chain compound beta-TeVO4

Helmuth Berger

Isotropic and anisotropic magnetic behavior of the frustrated spin-chain compound beta-TeVO4 is reported. Three magnetic transitions observed in zero magnetic field are tracked in fields applied along different crystallographic directions using magnetizati ...

Amer Physical Soc2016

Converse effect of pressure on the quadrupolar and magnetic transition in Ce3Pd20Si6

Henrik Moodysson Rønnow, Julio Antonio Larrea Jiménez

The heavy fermion compound Ce3Pd20Si6 displays unconventional quantum criticality as the lower of two consecutive phase transitions is fully suppressed by magnetic field. Here we report on the effects of pressure as an additional tuning parameter. Specific ...

Amer Physical Soc2016

Robust metastable skyrmions and their triangular-square lattice structural transition in a high-temperature chiral magnet

Henrik Moodysson Rønnow, Jonathan White

Skyrmions, topologically protected nanometric spin vortices, are being investigated extensively in various magnets(1-11). Among them, many structurally chiral cubic magnets host the triangular-lattice skyrmion crystal (SkX) as the thermodynamic equilibrium ...

Nature Publishing Group2016

Magnetic Hysteresis in Er Trimers on Cu(111)

Harald Brune, Stefano Rusponi, Marina Pivetta, Jan Gui-Hyon Dreiser, Christian Wäckerlin, Fabio Donati, Aparajita Singha, Romana Baltic

We report magnetic hysteresis in Er clusters on. Cu(111) starting from the size-of three atoms. combining Xray magnetic circular dichroism, scanning tunneling microscopy, and mean-field nucleation theory, we determine the size dependent magnetic properties ...

American Chemical Society2016

Luttinger liquid behavior in the alternating spin-chain system copper nitrate

Felix Groitl

We determine the phase diagram of copper nitrate Cu(NO3)(2)center dot 2.5D(2)O in the context of quantum phase transitions and novel states of matter. We establish this compound as an ideal candidate to study quasi-1D Luttinger liquids, 3D Bose-Einstein-Co ...

American Physical Society2015

Features of the magnetic properties of quasi-one-dimensional beta-TeVO4 magnets at low temperatures

Helmuth Berger

The effect of a magnetic field on the magnetic susceptibility chi(T) and the temperature of the three magnetic phase transitions in single-crystal beta-TeVO4 is studied at low temperatures. The H-T phase diagram is obtained for H parallel to b and H perpen ...

Amer Inst Physics2015

The Metallofullerene Field-Induced Single-Ion Magnet HoSc2N@C-80

Jan Gui-Hyon Dreiser

The low-temperature magnetic properties of the endohedral metallofullerene HoSc2N@C-80 have been studied by superconducting quantum interference device (SQUID) magnetometry. Alternating current (ac) susceptibility measurements reveal that this molecule exh ...

Wiley-Blackwell2014

An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK

Henrik Moodysson Rønnow, Julian Piatek

We describe the design of a low temperature scanning Hall probe microscope (SHPM) for a dilution refrigerator system. A detachable SHPM head with 25.4 mm OD and 200 mm length is integrated at the end of the mixing chamber base plate of the dilution refrige ...

American Institute of Physics2014

FH HES Optimization of Chemical Reactor Feed by Simulations Based on a Kinetic Approach

Thierry Meyer, Francis Stoessel, Charles Ibrahim Guinand

Chemical incidents are typically caused by loss of control, resulting in runaway reactions or process deviations in different stages of the production. In the case of fed-batch reactors, the problem generally encountered is the accumulation of heat. This i ...

Schweizerische Chemische Gesellschaft2014