PhD project: Interface coupling in ferroelectric/ferromagnetic/superconductor systems

Organisation/Company KU LEUVEN Research Field Physics » Solid state physics Physics » Quantum mechanics Physics » Applied physics Researcher Profile First Stage Researcher (R1) Application Deadline 15 Oct 2026 - 23:59 (UTC) Country Belgium Type of Contract Temporary Job Status Full-time Offer Starting Date 4 Jan 2027 Is the job funded through the EU Research Framework Programme? Not funded by a EU programme Reference Number BAP-2026-569 Is the Job related to staff position within a Research Infrastructure? No

Offer Description

In this PhD project we will study how a ferroelectric (FE) layer exerts an influence on a ferromagnetic (FM) layer, which in turn is interfaced with a superconducting (SC) layer, ultimately leading to electric control of the superconducting layer. The main goal of this approach is that the ferromagnetic configuration can be altered by an electric field rather than a magnetic field, which requires much less electric power and which is much more adapted for miniaturization. However, the physical properties, magnetic configuration, chemical composition and roughness at the interfaces of such FE/FM/SC heterostructures are still largely unknown and require systematic investigations.The main research questions to be addressed are therefore the following:

• What is the magnetic depth profile within the FE/FM/SC heterostructure?
• Can we tune the superconducting critical parameters of the SC layer by manipulating the magnetization direction in the FM layer via its coupling to a FE layer?

More specifically, we will synthesize a Si/FE/FM1/SC/FM2 heterostrucure. a first approach we will use BaTiO3 as FE, Fe as FM1 material, Co40Fe60 as FM2, and NbN as SC. The samples will be grown using the molecular beam epitaxy facilities in the KU Leuven Ion and Molecular Beam Laboratory (IMBL) facilities. Since the effects of interest are strongly dependent on the quality of the interfaces, special attention will be devoted to an in-depth study of their structural quality, including interface roughness and interdiffusion, precise layer thickness and local magnetization value. We will make use of X-ray scattering, scanning probe microscopy, Atom Probe Tomography, and Rutherford Backscattering techniques for the structural characterization. For the magnetic characterization we will mainly rely on magnetization measurements in our SQUID magnetometer and magnetotransport measurements at cryogenic temperatures to investigate the manipulation of the superconducting spin valve effect via the application of an electric field leading to a magnetoelectric coupling effect with the free layer in the stack. Since this will lead to an intricate magnetic structure near the interfaces, we will also make use of polarized neutron reflectivity and nuclear resonant scattering to study the magnetic depth profile in the layer stacks. We have extensive experience with both techniques (which will be performed at international large-scale international research facilities (such as ESRF in Grenoble, DESY in Hamburg and APS in Argonne), which will complement our in-house research.This PhD research project is carried out within the framework of a broader and long-lasting close collaboration with imec Leuven (Imec R&D, nano electronics and digital technologies).

• You are a motivated researcher with a Master in physics, chemistry, nanotechnology, or related fields, with a strong background in (experimental) solid state physics.
• You obtained excellent results in your prior studies and are fluent in both spoken and written English.
• You are a team player who actively shares experience and knowledge with colleagues.
• You are motivated to work in an international research team.
• You are enthusiastic about participating in experimental campaigns at large scale facilities, such as synchrotrons and neutron sources.
• Networking skills, creativity, persistence, and passion for what you do are highly valued.
• You will work in Leuven, a historic, dynamic and multicultural city located in the heart of Europe.
• As PhD researcher, you will follow a doctoral programme including personal training in management, science communication, and teaching. As part of the doctoral requirements, you will also take up a (limited) teaching task in Bachelor or Master programmes.
• We offer a stimulating work environment in a dynamic team of scientists at KU Leuven, an innovative and highly ranked university, recognised for its strong research profile and overall academic quality.
• You will work in Leuven, a historic, dynamic and multicultural city located in the heart of Europe.
• As PhD researcher, you will follow a doctoral programme including personal training in management, science communication, and teaching. As part of the doctoral requirements, you will also take up a (limited) teaching task in Bachelor or Mast