Our group, Hybrid Spintronics, focuses on the field-free control of spin states in various magnetic materials such as ferromagnets, antiferromagnets, altermagnets, and magnetic semiconductors. In particular, we investigate the control and readout of spin states using optical methods. Our experimental techniques include ultrafast optical spectroscopy, magneto-optic Kerr effect (MOKE) microscopy, and magnetotransport measurements.
Modern data storage technologies rely on different principles of information storage and can achieve different operational speeds determined by fundamental physical processes. Spintronics explores methods for operating data storage devices using magnetization and spins as memory storage media. For example, well-established memory technologies such as Hard Disk Drives (HDDs) rely on the manipulation of spin states in ferromagnets using external magnetic fields. The transition toward optical control of spin states enables the development of new concepts for information storage based on magnetic materials. Here, we aim to find systems and optical parameters for deterministic all-optical control in various systems. For this work, we employ various experimental methods such as MOKE microscopy, as well as optical spectroscopy.
Optically active semiconductors, such as metal halide perovskites, have great potential for applications such as light-emitting diodes (LEDs), optical detectors, and sensors. At the same time, they are promising candidates for opto-memory applications due to their strong interaction with light. Using ultrashort laser pulses, it is possible to induce various excitations in this class of materials, such as spin-polarized charge carriers, excitons, phonons, etc. In this work, we investigate the dynamical properties of these interactions on the picosecond timescale using ultrafast optical spectroscopy methods, particularly transient Faraday rotation spectroscopy and transient absorption (TA) spectroscopy with polarization analysis. Using ultrashort laser pulses with durations of a few tens of femtoseconds, we investigate spin and charge carrier dynamics in these materials, which can reach frequencies in the THz range.
Altermagnets are a novel class of magnetic materials that combine properties of both antiferromagnets and ferromagnets. Similar to antiferromagnets, altermagnets exhibit antiparallel spin arrangements, resulting in ultrafast spin dynamics in the THz range. However, unlike conventional antiferromagnets, their electronic bands are not Kramers-degenerate, making them resemble ferromagnets in certain aspects. In particular, despite their antiparallel spin structure, effects such as giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) have been predicted in altermagnetic systems due to spin splitting of the band structure.
In our work, we investigate the physical phenomena occurring in altermagnets under optical excitation, as well as the manipulation of domain structures and spin states using optical means.
