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Tamás Prok

Publications and source records attributed to Tamás Prok.

4 recordsLinked to original sources

Efficient non-volatile electric control of magnetosensing in CrSBr

In two-dimensional crystals, electrostatic gating can modulate the charge carrier density, thereby tuning their electrical properties. In magnetic materials such as CrSBr, this approach can also enable direct electrical control of magnetoresistance. Non-volatile gating is particularly attractive since it allows the carrier density to be maintained at a desired level without the need for a continuous gate bias, offering significant advantages for technological applications. Here, we demonstrate a simple device architecture in which a solution-processed ferroelectric P(VDF-TrFE) layer is integrated directly onto a CrSBr channel, enabling non-volatile control of its magnetoresistance. We investigate the magnetotransport response over a broad temperature range and demonstrate a reproducible and robust gate dependence. Notably, the ferroelectric gate achieves a gating efficiency approximately one order of magnitude higher than that of a conventional SiO$_2$ dielectric, highlighting the potential of ferroelectric gating for electrical control of 2D magnetic materials.

cond-mat.mes-hall

Effect of pressure on the magnetic properties of (Co$_{0.5}$Fe$_{0.5}$)$_5$GeTe$_2$

Cobalt-doped Fe$_5$GeTe$_2$ possesses a rich magnetic phase diagram as a function of Co concentration. The nature of magnetic order in (Co$_{0.5}$Fe$_{0.5}$)$_5$GeTe$_2$ is especially interesting, as it has been shown to exhibit ferromagnetic order, A-type antiferromagnetic (AFM) order, or potentially both at the same time. Here we present magnetoresistance measurements on antiferromagnetic (Co$_{0.5}$Fe$_{0.5}$)$_5$GeTe$_2$ at a series of pressures and extract the anisotropy and interlayer exchange fields using the two-sublattice model. We show a 50 % increase of the interlayer exchange at 2 GPa, highlighting the sensitivity of magnetic properties to interlayer distance. In addition, we find that the sharp hysteretic transitions observed within the AFM state can be qualitatively described by a linear chain model, which suggests an even-odd effect as a function of layer number instead of a coexisting ferromagnetic phase.

cond-mat.mes-hall

Impact of current-induced magnons on spin-orbit torque analysis

The second-harmonic Hall technique is a widely used, sensitive method for studying the spin-orbit torques generated by charge current. It exploits the dependence of the Hall resistance on the magnetization direction, although thermal phenomena also contribute. Historically, deviations from the expected magnetic field dependence have usually been neglected. Based on our studies on permalloy/platinum bilayers, we show that a counterpart to the magnon-related spin-flip unidirectional magnetoresistance - known to appear in the second-harmonic longitudinal resistance - appears in the Hall data, and that describing the results in a wide field range with these contributions is essential to accurately estimate the torques.

cond-mat.mes-hall

Near-surface InAs 2DEG on a GaAs substrate: characterization and superconducting proximity effect

We have studied a near-surface two-dimensional electron gas based on an InAs quantum well on a GaAs substrate. In devices without a dielectric layer we estimated large electron mobilities on the order of $10^5$ cm$^2$/Vs. We have observed quantized conductance in a quantum point contact, and determined the g-factor. Using samples with an epitaxial Al layer, we defined multiple Josephson junctions and found the critical current to be gate tunable. Based on multiple Andreev reflections the semiconductor-superconductor interface is transparent, with an induced gap of 125 $μ$eV. Our results demonstrate the viability of this platform for hybrid topological superconductor devices.

cond-mat.mes-hall