Leibniz Institute for Crystal Growth (IKZ), Berlin

The Leibniz-Institut für Kristallzüchtung (IKZ) is a leading research institution in the field of science & technology as well as service & transfer of crystalline materials. Our goal is to enable solutions for pressing societal challenges (e.g. communication, artificial intelligence, climate protection, health, etc.) through modern electronic & photonic technologies. The work covers the entire spectrum from basic and applied research to pre-industrial development and is carried out in cooperation with national and international partners from universities, academies and industry. The institute is part of the Forschungsverbund Berlin (https://www.fv-berlin.de/) and part of the Leibniz Association (https://www.leibniz-gemeinschaft.de). You can find more details on the institute webpage: https://www.ikz-berlin.de.

The Leibniz-Institut für Kristallzüchtung currently offers a

Research Assistant (m/f/d)

"Investigation of atomic and microscopic mechanisms of electromechanical coupling in uniaxial ferroelectrics”.

Electromechanical coupling is the ability of some solids to convert mechanical and electrical energies into one another. This physical phenomenon is of huge academic and industrial interest. Perovskite oxides ferroelectrics, usually lead-based, are currently the largest group of industrially relevant electromechanically active materials and used in pressure sensors, actuators, transducers, etc.

Fundamental knowledge of the structural mechanisms behind electromechanical coupling will allow for their systematic exploitation and go beyond the empirical approaches to optimize the functional materials properties. A detailed study of these fundamental mechanisms in industrially relevant materials is generally hindered by the additional presence of ferroelasticity. Uniaxial, ferroelectric single crystals, are free from ferroelastic domains and therefore most suitable to analyze the structural response under external electric field.

This project aims for a detailed understanding of the role of purely ferroelectric domains in electromechanical coupling. These domains form to balance energy contributions from internal stresses and electric fields. In some materials, this can lead to anomalous enhancement of the electromechanical coupling. The objective is to quantify the crystallographic and domain-related changes in such materials for any state along the ferroelectric hysteresis loop. Furthermore, the concept of electrostriction as origin of piezoelectricity in polar materials will be explored and tested.

The Research Assistant will focus on the characterization of the structure of single-crystals subjected to time-dependent electric fields. Uniaxial ferroelectrics grown by dedicated IKZ groups are available for this study. The work involves time- and field-dependent X-ray diffraction (XRD) measurements both in IKZ labs and synchrotron radiation sources such as the ESRF, DESY or BESSY. Spatially resolved characterization on the microscale will be performed to study the influence of domain walls on elastic strain and polarization fields. The work will also include complementary characterization by laser interferometry and piezo-force microscopy (PFM) at IKZ and by electrical measurements. The project will be carried out in collaboration with Tel-Aviv University (TAU) and TU Bergakademie Freiberg, which requires regular scientific exchange for success. This will also involve joint (virtual) meetings and joint experiments at synchrotron sources. The work can partially be carried out remotely, while long-term lab-visits (several weeks per year) at the mentioned partner institutions will be required.

Requirements:

• MSc degree in physics, materials science, or in a related discipline
• Basic knowledge of programming in ideally in Python
• Self-management and active collaboration in a team of scientists, technicians and students
• Good knowledge of the English language. A basic knowledge of German is beneficial.

Prior experience in the following fields is an asset to your application:

• Hands-on experience in single-crystal X-ray diffraction (high resolution or structure determination) for bulk or thin-films characterization
• Any experience in the usage of synchrotron radiation
• Electrical measurements (I-V / P-E loops) and electrical circuitry
• Education in crystallography

What we offer

The position is limited to two years. Payment is according to TVöD Bund (Treaty for German public service) 50% E13 including the usual social benefits (30 vacation days in a 5-day week, flexible working hours). The Leibniz-Institut für Kristallzüchtung actively promotes the development of young scientists and follows the guidelines of the Leibniz Association.

The Leibniz-Institut für Kristallzüchtung actively supports a healthy work-life balance and is an equal opportunities employer. Female candidates are encouraged to apply and will be given preference if suitably qualified. Among equally qualified candidates, preference will be given to candidates with disabilities. IKZ promotes diversity. We welcome every qualified application, regardless of age, belief, disabilities, ethnic origin, gender, nationality, religion, or sexual orientation.

For information about the project please contact:

Dr. Carsten Richter, Tel. +49 (30) 246499 516, carsten.richter(at)ikz-berlin.de

Have we aroused your interest?

Then apply with a letter of motivation, curriculum vitae and all relevant certificates. To do so, please go to Job offers/jobs on our homepage and click on this advertisement and then on "Apply online". Applications will be accepted until the position is filled.

We are looking forward to receiving your application!