Author Archives: SAM

Make Science More Diverse, Equitable, and Open to All – Women in STEM

PICTURE A SCIENTIST is a movie laying out the situation of women in STEM. Join us for a narration of a journey full of struggle and harassment presented by biologist Dr. Nancy Hopkins, chemist Dr. Raychelle Burks, and geologist Dr. Jane Willenbring, based on their very own life and career experience.

"Picture a Scientist is the documentary we need to continue the call for action, to continue awareness, and to remind those who would abuse a system, we see you. " - Film Inquiry

When: In your own time between Friday, 11 December (noon CET) – Sunday, 13 December (midnight CET)

Where: In the comfort of your home

Registration required: Please fill out this form by Tuesday, 8 December (midnight CET), to register. You will receive personalized login details following your registration, which you can use to watch the film.

Find more information about the film on this website.

The screening is organized by SAM - the Scientific Staff Association at the Department of Materials, kindly sponsored by the Department of Materials, ETH Zurich and is receiving advertising support by Equal!

Materials Colloquium 2020 - December, 2nd, 16:30

Zoom

Laura Alvarez (Laboratory for Soft Materials and Interfaces, D-MATL, ETHZ)

Programming the dynamics of artificial microswimmers provides a benchmark towards the realization of smart microscale devices. Motile microorganisms, such as bacteria, have developed sophisticated mechanisms to regulate their dynamics based on environmental changes [1]. The creation of artificial programmable microswimmers capable of reproducing such complex performance using much simpler structures remains an open challenge [2]. Here we present two strategies to create artificial microscale active agents that are able to move, sense and respond to external stimuli [3-5]. In both cases, a real time feedback with the environment dictates the swimming behavior of artificial microswimmers. This new generation of adaptive active colloids constitutes an important step in the pursuit of autonomous microsystems with potential applications in microrobotics.

[1] K. Son, et.al. Nature Reviews, 13, 761-775 (2015).
[2] C. Bechinger, et.al., Revi. Mod. Phys, 88, 045006-045056 (2016).
[3] M. A Fernandez-Rodriguez et.al, Nature Communications, 11, 4223 (2020).
[4] A. R. Sprenger et.al., Langmuir, 36, 25 (2020).
[5] L. Alvarez et.al, submitted (2020).

Overview Materials Colloquium 2020

Materials Colloquium 2020 - December, 2nd, 16:30

Zoom

Marta Gibert (Physik-Institut, University of Zurich)

The large variety of functionalities exhibited by transition metal oxides places them as highly attractive materials both from a fundamental and applied point of view. Furthermore, the possibility to assemble oxides in epitaxial heterostructures allows us to further tune their properties and even access novel electronic behaviours not displayed by the parent compounds. Here, we will use atomically-controlled NdNiO3/SmNiO3 superlattices to show that the length scale of the interfacial coupling between metal and insulator phases is determined by balancing the energy cost of the boundary between a metal and an insulator and the bulk phase energies [1]. The structure-property relation of ferromagnetic La2NiMnO6 thin films as their thickness is reduced to just few unit cells will also be presented.

[1] Dominguez et al., Nature Materials 19, 1182 (2020)

Overview Materials Colloquium 2020

Materials Colloquium 2020 - November, 4th, 16:30

Zoom

Sebastian Stepanow (Magnetism and Interface Physics, D-MATL, ETHZ)

Magnetic resonance techniques are widely employed for probing the electronic and magnetic properties of solids, liquids, and molecules as well as for their elemental and structural characterization. These techniques probe with high precision the excitation of the magnetic states of an atom, or of a nucleus, and provide information on their chemical environment. For instance, electron paramagnetic resonance (EPR) is routinely used for non-invasive spin detection in materials science and chemistry research. However, conventional magnetic resonance techniques can only detect a macroscopic number of spins (~107 electron spins, ~1012 nuclear spins) and have poor spatial resolution. Scanning tunneling microscopy (STM), on the other hand, is a unique technique to achieve subatomic spatial resolution with simultaneous local spectroscopic information of single atoms and molecules on conductive surfaces.  Recently, the two techniques were combined to probe magnetic interactions and properties of single spins on surfaces. In this presentation, I will introduce the EPR-STM technique and highlight recent advances. 

Overview Materials Colloquium 2020

Materials Colloquium 2020 - November, 4th, 16:30

Zoom

Anna Fontcuberta i Morral (Laboratory of Semiconductor Materials, EPFL)

Solar energy harvesting constitutes of the technological paths to replace production of electrical power by burning fossil fuels. Some compound semiconductors such as GaAs and InGaAsP exhibit a high absorption coefficient in the photon energy of interest for solar energy conversion. Their commercial potential in terrestrial applications is reduced due to the scarcity (and thus high cost) of group III elements such as In and Ga. In this talk we present two approaches to render the use of this kind of materials sustainable: a strong reduction in material use through nanostructures and the replacement of group III by group II such as zinc. We find nanostructures also provide a path to increase light collection [1]. We show how II-V compounds such as Zn3P2 exhibit one magnitude higher absorption coefficient than GaAs [2]. We explain how these materials can be fabricated with high crystal quality, opening the path for the creation of alternative and sustainable compound semiconductor solar cells [3,4].

[1] P. Krogstrup et al Nature Photon 7, 306 (2013)
[2] M.Y. Swinkels et al Phys. Rev. Appl. 14, 024045 (2020)
[3] S. Escobar Steinvall et al Nanoscale Horizons 5, 274-282 (2020)
[4] R. Paul et al, Crys. Growth. Des. 20, 3816–3825 (2020)

Overview Materials Colloquium 2020

Materials Colloquium 2020 - October, 7th, 16:30

Zoom

Ahmad Rafsanjani (SDU Biorobotics, University of Southern Denmark)

Soft robotics surged a bioinspired evolution in robot design through their highly deformable structure by enabling robots to interact adaptively with complex environments and cooperate safely with humans. Flexible mechanical metamaterials are compliant structures with exotic mechanical properties and complex deformation behavior associated with their unique architecture rather than their chemical makeup. Integrating the complex behavior of highly deformable metamaterials into the function of soft robots allows us to embody intelligent behavior into their structure and substantially enhance their performance. In this talk, I will present several examples in which flexible metamaterials can enable us to assign primitive forms of intelligent behavior to the body of soft robots and perform simple tasks.

Overview Materials Colloquium 2020

Materials Colloquium 2020 - October, 7th, 16:30

Zoom

Brendan Bulfin (Professorship of Renewable Energy Carriers, D-MAVT, ETH Zürich)

Metal oxide redox cycles offer a pathway for converting heat into chemical energy via the thermal reduction of a metal oxide. The reduced metal oxide can then be used in a number of applications by re-oxidized it in a second step, utilizing the stored chemical energy and returning the oxide to its original state. Applications include; thermochemical fuel production via water or carbon dioxide splitting, thermal energy storage, and oxygen storage and separation. Here we discuss these applications, with a focus on the redox materials and their requirements. The crucial limiting factors for these applications are the thermodynamics of the reactions, which depend strongly on the choice of oxide. These limitations will be discussed along with developments in the field. Finally, a large material screening study of perovskite oxides will be presented.

Overview Materials Colloquium 2020

Dear members of SAM,

We are happy to invite you to the SAM General Assembly this year via ZOOM (see link below) to vote a new board, discuss association matters and bring in ideas for the coming year.

The SAM member joining with the most creative ZOOM background will receive a small prize. 

Join us, tell us what you liked so far and what you wish for in the future. Simply send us an email and we will address your ideas during the event.

Also, if you are interested in getting more involved in the “behind the scenes” of the Department of Materials, our GA is a good time to get to meet the SAM board and join it to become an active member of SAM.

Date: 23 September 2020
Time: 10 AM
Place: ZOOM (https://ethz.zoom.us/j/91297904514) - Password: 443411

The agenda:
1. Welcome
2. Election of the vote counter
3. Approval of the minutes of the GA 2019
4. Report from the board
A. Presentation of the association and the board
B. Highlights of the past year
C. Outlook
5. Finances 2019/2020 (expenses/budget)
6. Election of one to two financial revisers
7. Discharge of the board
8. Election of the board members and their functions
9. Varia

We are looking forward to seeing you there!

Your SAM-team
Cameron, Chia, Laura, Linda, Maria-Nefeli, Martina, Murielle, Nicolas, Štefan, Tobias, Viktor, Vladimir

Materials Colloquium 2020 - September, 9th, 16:30

Zoom

Roland Logé (Laboratory of Thermomechanical Metallurgy, Institute of Materials, EPFL)

Laser Powder Bed Fusion (LPBF, also known as SLM, Selective Laser Melting) is a well known Additive Manufacturing technology, among the most studied in literature for metals and alloys. A number of drawbacks however still limit its range of applications, among which : (i) the high level of residual stresses; (ii) the often narrow safe processing window, which does not leave much space for microstructure optimization; (iii) the time consuming search for optimum laser parameters, which is material and machine dependent, and also relates to the part size and shape. To solve some of these issues, we introduce a new hybrid “3D LSP” manufacturing process, combining Laser Shock Peening (LSP) with LPBF. 3D LSP can efficiently strain harden a metal and convert LPBF induced Tensile Residual Stresses into CRS. It opens a range of new possibilities such as increased fatigue life or geometrical accuracy, 3D design of grain structures, and improved processability. We also present a new “translation rule”, which is able to predict optimum LPBF parameters for one material, based on those found for another material, using the concept of normalized enthalpy.

Overview Materials Colloquium 2020

Materials Colloquium 2020 - September, 9th, 16:30

Zoom

Chiara Gattinoni (Materials Theory, D-MATL, ETH Zürich)

A precise understanding of the surface and interface behavior of ferroelectric materials is necessary towards their use in promising applications such as memory storage or catalysis. In this seminar I will focus on the example of lead titanate and bismuth ferrite to describe how structural and electronic properties affect ferroelectricity at the nanoscale. I will show that surfaces and interfaces play a pivotal role in (de)stabilizing the ferroelectric polarization in thin films and nanoparticles. I will then investigate how the special properties of ferroelectric surfaces can be used to create efficient catalytic devices.

Overview Materials Colloquium 2020