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

Role: PhD Thesis - Ultrafast Electron Holography of Cobalt Nanowires Using GHz RF Electron Beam Pulser
Organisation: Forschungszentrum Jülich (Helmholtz Association of German Research Centres)
Location: Jülich, Germany
Contract Type: Fixed term of 3 years (possibility to extend to 4 years)
Salary: Pay group 13 (75%) TVöD-Bund, plus year-end bonus and capital-forming benefits

Role Overview
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.

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).

Responsibilities
- 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.

Requirements and Qualifications
- 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.
- Ability to 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.

What They Offer
- Team & Environment: Work in a motivated team with an international and interdisciplinary focus at one of the largest research institutions in Europe.
- Research & Infrastructure: Access to excellent scientific and technical facilities for your work.
- Supervision & Support: Continuous, expert guidance from your academic supervisor throughout your doctoral studies.
- Work-life balance: Flexible working hours to help balance professional and personal life, with options for flexible working location after consultation.
- Annual Leave: 30 days of annual leave.
- Knowledge & Development: Support for professional development through training and networking opportunities specifically for doctoral candidates (JuDocS).
- Fair remuneration: Classification according to pay group 13 (75%) of the TVöD-Bund, including a year-end bonus (75% of a monthly salary) and capital-forming benefits.
- Perspective: Fixed-term position of 3 years with the possibility to extend the contract to 4 years in total.
- Support for international employees: Assistance from the International Advisory Service to help international employees get started.
- Diversity and Inclusion: A diverse and inclusive working environment with equal opportunities.