Postdoctoral Researcher in Data-Driven Micromagnetic Modelling

The Department of Earth Sciences is looking for a highly motivated Postdoctoral candidate with a PhD background in Earth Sciences or another appropriate field. You will work on the project “Data-Driven Micromagnetic Modelling”. Your job This study contributes to SPARK, an ERC Consolidator project that aims to unlock magnetic information stored in nanoscale vortex-state particles in rocks and other geological materials. These particles are predicted to be exceptionally stable magnetic recorders, yet their internal magnetic structure and recording behaviour remain largely enigmatic. Your work will focus on developing computational tools to bridge the gap between high-resolution magnetic observations and micromagnetic simulations. You will lead the computational and data-driven development of a novel extension to the micromagnetic modelling code MERRILL, enabling reconstruction of internal magnetic configurations in individual vortex-state particles directly from experimental data. Your main tasks and responsibilities include:

• Assessing the magnetic stability of vortex-state particles as a function of their size, shape, and mineralogy by developing data-driven micromagnetic computational simulations.
• Extending MERRILL with a data-driven workflow that incorporates constraints from Quantum Scanning Microscope and slice-and-view FIB-SEM measurements, enabling efficient convergence towards the most likely internal magnetic configuration of a particle.
• Contributing to the acquisition, processing, and interpretation of both high-resolution wide-field Quantum Diamond Microscope and Quantum Scanning Microscope data.
• Publishing both your scientific findings and the tools developed in a FAIR manner, contributing to open and reusable science and computational workflows.

You will work closely with two PhD candidates, who focus on the empirical characterization of vortex-state particles and the development of Nanomagnetic Tomography, and bring a geology-oriented background (e.g. from mineralogical or petrological courses or research projects during BSc and MSc studies). Together, you will combine complementary computational and experimental approaches to establish a robust, data-driven framework for identifying which vortex-state particles reliably record the Earth’s magnetic field. The development of the MERRILL extension will be done in collaboration with prof. Williams from Edinburgh University and prof. Fabian from NTNU Trondheim. The project is embedded in the Paleomagnetic Laboratory Fort Hoofddijk, which hosts two Quantum Diamond Microscopes and a Quantum Scanning Microscope, enabling magnetic imaging at spatial resolutions from micrometres down to the nanometre scale. Advanced FIB-SEM facilities are available at Utrecht University’s Electron Microscopy Center. The project further benefits from excellent dedicated CPU and GPU computing infrastructure to support large-scale numerical modelling and data analysis. This is a full-time, two-year postdoctoral position funded by an ERC Consolidator Grant ‘SPARK’ awarded to Dr Lennart de Groot. Your qualities You should have:

• A PhD degree in Earth Sciences, Physics, Applied or Computational Mathematics, Material Sciences, or a closely related discipline, at the time of the start of the contract.
• A strong background in computational or numerical modelling, preferably with demonstrated experience in one or more of the following: micromagnetic modelling, inverse problems, or nano- to micro-scale magnetism.
• The ability to work independently on complex computational problems while collaborating effectively within a multidisciplinary research team.
• Proficiency in spoken and written English for academic purposes.

Preferably, you will also have:

• Experience with, or a strong interest in, nanoscale magnetic imaging techniques, such as Quantum Diamond Microscopy, Quantum Scanning Microscopy, or related methods.
• Experience with FIB-SEM imaging and/or data processing, or enthusiasm for acquiring these skills.
• Experience with the MERRILL micromagnetic modelling framework, or closely related modelling environments.
• A motivation to contribute to open and FAIR sciences, including publishing both scientific results and computational tools.

We strongly encourage applications from candidates with diverse backgrounds and career paths who are enthusiastic about working at the interface of computation, experimentation, and Earth sciences. If you are passionate about this research but uncertain whether your background fits perfectly, we encourage you to apply. Our offer We offer:

• a position (1.0 FTE) for 24 months.
• a working week of 36 - 40 hours and a gross monthly salary between € 3.546 and €5.538 in the case of full-time employment (salary scale 10 under the Collective Labour Agreement for Dutch Universities (CAO NU));
• 8% holiday pay and 8.3% year-end bonus;
• a pension scheme, partially paid parental leave and flexible terms of employment based on the CAO NU.

In addition to the terms of employment laid down in the CAO NU, Utrecht University also offers a range of its own schemes for employees. This includes arrangements for professional development, various types of leave, and options for sports and cultural activities. You can also tailor your employment conditions through our Terms of Employment Options Model. In this way, we encourage you to keep investing in your personal and professional development. For more information, please visit Working at Utrecht University. About us A better future for everyone. This ambition motivates our scientists in executing their leading research and inspiring teaching. At Utrecht University, the various disciplines collaborate intensively towards major strategic themes. Our focus is on Dynamics of Youth, Institutions for Open Societies, Life Sciences and Pathways to Sustainability. Sharing science, shaping tomorrow. Utrecht University’s Faculty of Geosciences studies the Earth: from the Earth’s core to its surface, including man’s spatial and material utilisation of the Earth – always with a focus on sustainability and innovation. With 3,400 students (BSc and MSc) and 720 staff, the faculty is a strong and challenging organisation. The Faculty of Geosciences is organised in four Departments: Earth Sciences, Human Geography & Spatial Planning, Physical Geography, and Sustainable Development. The Department of Earth Sciences conducts teaching and research across the full range of the solid Earth and environmental Earth sciences, with activities in almost all areas of geology, geochemistry, geophysics, biogeology and hydrogeology. Our key research themes are Earth & Planetary Processes, Sustainable Use of the Subsurface, Planetary Health & Environment, and Climate & Life. The department hosts a highly international tenured staff. Besides the Paleomagnetic Laboratory, we house or have access to a wide variety of world-class laboratories, among which are UU’s Electron Microscopy Centre, the Geolab, and the Earth Simulation Lab. We also have excellent High- Performance Computing facilities and organise a warm welcome for every new member.. More information For more information (not for application) about this position, please contact Dr Lennart de Groot at l.v.degroot@uu.nl. Candidates for this vacancy will be recruited by Utrecht University. Apply now As Utrecht University, we want to be a home for everyone. We value staff with diverse backgrounds, perspectives and identities, including cultural, religious or ethnic background, gender, sexual orientation, disability or age. We strive to create a safe and inclusive environment in which everyone can flourish and contribute. Knowledge security screening can be part of the selection procedures of academic staff. We do this, among other things, to prevent the unwanted transfer of sensitive knowledge and technology. You can only apply via our online application system using the 'Apply now' button. Applications submitted by email cannot be considered. Please include the following documents with your application:

• A letter of motivation, describing why this postdoctoral position fits your background and interests, and how your expertise would contribute to the project. Please also explain why you are interested in working at Utrecht University and within the Department of Earth Sciences.
• A curriculum vitae, including relevant research experience, publications, and work carried out during your PhD and/or previous postdoctoral positions.
• The names and contact details (including email addresses) of at least two referees.

No reference letters are required at the time of application. If you are shortlisted, we will contact your referees, but only after informing you in advance. We aim to complete the selection procedure shortly after the application deadline of 15 February 2026. Interviews are expected to take place in calendar weeks 9, 10, or 11, and the initial interview may be conducted via video call or in person. However, before a final offer is made, an in-person meeting at Utrecht University and the paleomagnetic lab Fort Hoofddijk is required. The preferred starting date is spring or summer 2026, although some flexibility is possible. Note that international candidates that need a visa/work permit for the Netherlands require at least four months processing time after selection and acceptance. This will be arranged with help of the International Service Desk (ISD) of our university. Finding appropriate housing in or near Utrecht is your own responsibility, but the ISD may be able to advise you therewith. Unfortunately, we must warn that it is a tight market at the moment. In case of general questions about working and living in The Netherlands, please consult the Dutch Mobility Portal. Online screening may also be part of the selection. Commercial response to this ad is not appreciated.