PhD Thesis - Ultrafast Electron Holography of Cobalt Nanowires Using GHz RF Electron Beam Pulser

Forschungszentrum Jülich’s Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), specifically the Physics of Nanoscale Systems (ER-C-1), is a world-class research institute focused on understanding and engineering materials at the atomic scale. Using state-of-the-art electron microscopy and spectroscopy, the institute develops new experimental methods to reveal how nanoscale structures determine magnetic, electronic, catalytic, and soft-matter properties. Its research supports major challenges in energy conversion and storage, advanced materials, nanotechnology, and emerging life-science applications. ER-C-1 also operates as part of a national user facility, giving academic and industrial researchers access to cutting-edge instruments, expert support, and collaborative opportunities in an international environment—making it an outstanding place for PhD candidates to carry out high-impact, interdisciplinary research.

Your Job

The PhD project investigates ultrafast magnetisation dynamics in cobalt nanowires using time-resolved off-axis electron holography with picosecond temporal resolution in a transmission electron microscope retrofitted with an RF-based electron beam pulser. The aim is to probe coherent magnetisation precession and map the spatial evolution of magnetic domains during switching events by applying GHz microwave pump pulses resonant with the nanowire’s ferromagnetic resonance frequency. This work will establish a new methodology for studying nanoscale magnetic dynamics relevant to next-generation magnetic memory and logic devices. This project offers the opportunity to work at the intersection of ultra-fast electron microscopy, RF physics, magnetism, and electron holography. The project will be carried out in close collaboration with Dr. Thomas Lagrange (EPFL).

Your Tasks in detail:

• Design and execute GHz microwave pump–probe experiments to excite and measure ultrafast magnetisation reversal and precessional dynamics in cobalt nanowires with picosecond temporal resolution.
• Develop and optimise time-resolved electron holography protocols to achieve nanometre-scale (~1 nm) spatial resolution under low pulse current conditions, including signal-to-noise (SNR) enhancement strategies.
• Analyse phase-resolved holographic data to quantitatively extract local magnetic field distributions, spin-wave propagation velocities, domain-wall motion, and magnetic damping parameters.
• Documentation and publication of results in reports, scientific manuscripts, and conference presentations in English
• Collaboration with and co-supervision of Master's students and research interns

Your Profile

• Excellent completed master's degree in physics, material sciences, engineering, or a related field.
• Solid knowledge of semiconductor physics, lasers, and optics.
• Ideally, experience in the field of transmission electron microscopy.
• High level of self-motivation, as well as enjoyment and skill in practical work.
• Willingness to take on responsibility for the laboratory and equipment.
• A high level of teamwork and enjoyment of cooperative collaboration.
• Furthermore, you can quickly familiarize yourself with new methods and techniques.
• Ability to work cooperatively with internal and external project partners.
• Very good command of written and spoken English with extensive vocabulary is required (at least B2 level according to the CEFR), ideally supported by a certificate confirming the language level.

Our Benefits for You

• Team & Environment: You will work in a motivated team with an international and interdisciplinary focus – at one of the largest research institutions in Europe
• Research & Infrastructure: You will have access to excellent scientific and technical facilities for your work
• Supervision & Support: We will accompany your doctoral studies with continuous, expert guidance from your academic supervisor
• Work-life balance: We offer flexible working hours to help you balance your professional and personal life. You also have the option of flexible working (in terms of location), which is generally possible after consultation and in line with upcoming tasks and (on-site) appointments
• Annual Leave: You get 30 days of annual leave
• Knowledge & Development: Your professional development is important to us – we support you specifically and individually e.g., through training and networking opportunities specifically for doctoral candidates (JuDocS)
• Fair remuneration: Depending on your qualifications and assigned responsibilities, you will be classified according to pay group 13 (75%) of the TVöD-Bund. In addition to the basic salary, there is an additional year-end bonus under the collective pay agreement amounting to 75% of a monthly salary, as well as capital-forming benefits. All information about the TVöD-Bund collective agreement can be found on the BMI website (pay scale table on page 66 ff. of the PDF download)
• Perspective: The position is for a fixed term of 3 years with the possibility to extend the contract to 4 years in total
• Support for international employees: Our International Advisory Service makes it easier for international employees to get started

In addition to exciting tasks and a collegial working environment, we offer you much more: https://go.fzj.de/benefits

We welcome applications from people with diverse backgrounds, e.g. in terms of age, gender, disability, sexual orientation / identity, and social, ethnic and religious origin. A diverse and inclusive working environment with equal opportunities in which everyone can realize their potential is important to us.

The following links provide further information on diversity and equal opportunities: https://go.fzj.de/equality and on specific support options: https://go.fzj.de/womens-job-journey

Place of Employment: Jülich

Start Date:To the next possible date

Salary: Pay group 13 (75%) TVöD-Bund

Application Deadline: The position will be advertised until it is successfully filled.

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