Publications de Péter Szirmai

Perovskite-based detector for reactor dosimetry monitoring

László Forró, Endre Horvath, Pavel Frajtag, Andreas Pautz, Péter Szirmai, Márton Kollár

Hybrid halide perovskites have demonstrated significant efficiency in detecting a broad spectrum of high-energy radiation, including X-rays, gamma rays (γ-rays), and neutrons. Given the common occurrence of mixed radiation fields, we investigated the perfo ...

EDP Sciences2024

Ultralong 100 ns spin relaxation time in graphite at room temperature

László Forró, Bálint Náfrádi, Péter Szirmai, Bence Gábor Márkus

Graphite has been intensively studied, yet its electron spins dynamics remains an unresolved problem even 70 years after the first experiments. The central quantities, the longitudinal (T-1) and transverse (T-2) relaxation times were postulated to be equal ...

Nature Portfolio2023

Intermolecular Resonance Correlates Electron Pairs Down a Supermolecular Chain: Antiferromagnetism in K-Doped p-Terphenyl

László Forró, Bálint Náfrádi, Péter Szirmai

Recent interest in potassium-doped p-terphenyl has been fueled by reports of superconductivity at T-c values surprisingly high for organic compounds. Despite these interesting properties, studies of the structure-function relationships within these materia ...

AMER CHEMICAL SOC2020

Tuning ferromagnetism at room temperature by visible light

László Forró, Bálint Náfrádi, Massimo Spina, Endre Horvath, Xavier François Mettan, Andrea Pisoni, Péter Szirmai

Most digital information today is encoded in the magnetization of ferromagnetic domains. The demand for ever-increasing storage space fuels continuous research for energy-efficient manipulation of magnetism at smaller and smaller length scales. Writing a b ...

National Academy of Sciences2020

Light-induced charge transfer at the CH3NH3PbI3/TiO2 interface-a low-temperature photo-electron paramagnetic resonance assay

Philippe Bugnon, László Forró, Andrzej Sienkiewicz, Bálint Náfrádi, Endre Horvath, Péter Szirmai, Pavao Roko Andricevic, Anastasiia Glushkova, Márton Kollár, Konstantins Mantulnikovs

The performance of organic-inorganic metal halide perovskites-based (MHPs) photovoltaic devices critically depends on the design and material properties of the interface between the light-harvesting MHP layer and the electron transport layer (ETL). Therefo ...

2020

Ultralong Spin Lifetime in Light Alkali Atom Doped Graphene

László Forró, Bálint Náfrádi, Péter Szirmai, Bence Gábor Márkus

Today's great challenges of energy and informational technologies are addressed with a singular compound, Li-and Na-doped few-layer graphene. All that is impossible for graphite (homogeneous and high-level Na doping) and unstable for single-layer graphene ...

AMER CHEMICAL SOC2020

Quantum spin-liquid states in an organic magnetic layer and molecular rotor hybrid

László Forró, Bálint Náfrádi, Andrea Pisoni, Péter Szirmai, Edoardo Martino, Konstantins Mantulnikovs

The exotic properties of quantum spin liquids (QSLs) have continually been of interest since Anderson's 1973 ground-breaking idea. Geometrical frustration, quantum fluctuations, and low dimensionality are the most often evoked material's characteristics th ...

National Academy of Sciences2020

Tuning Conductivity and Spin Dynamics in Few-Layer Graphene via In Situ Potassium Exposure

László Forró, Bálint Náfrádi, Péter Szirmai, Olivér Sági, Ferenc Simon, Sándor Kollarics, Bence Gábor Márkus

Chemical modification such as intercalation or doping of novel materials is of great importance for exploratory material science and applications in various fields of physics and chemistry. Herein, the systematic intercalation of chemically exfoliated few- ...

2020

Tailoring thermal conduction in anatase TiO2

Luca Rossi, Helmuth Berger, László Forró, Jacim Jacimovic, Endre Horvath, Xavier François Mettan, Andrea Pisoni, Péter Szirmai

Thermal conductivity (κ) plays an essential role in functional devices. It is advantageous to design materials where one can tune κ in a wide range according to its function: single-crystals and nanowires of anatase polymorph of titanium dioxide, broadly u ...

Springer2019

Improved Alkali Intercalation of Carbonaceous Materials in Ammonia Solution

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon, Sándor Kollarics, Bence Gábor Márkus

Alkali-intercalated graphite compounds represent a compelling modification of carbon with significant application potential and various fundamentally important phases. The intercalation of graphite with alkali atoms (Li and K) using liquid ammonia solution ...

WILEY-V C H VERLAG GMBH2019

Characterizing the maximum number of layers in chemically exfoliated graphene

László Forró, Bálint Náfrádi, Péter Szirmai, Julian Ayrton Englert, Ferenc Simon, Bence Gábor Márkus

An efficient route to synthesize macroscopic amounts of graphene is highly desired and bulk characterization of such samples, in terms of the number of layers, is equally important. We present a Raman spectroscopy-based method to determine the typical uppe ...

Springer Nature2019

Frustration and Randomness : Magnetic Studies of Organic Quantum Spin Liquids

Péter Szirmai

Spin systems with strong magnetic interactions might remain disordered avoiding conventional magnetic long-range ordering due to zero-point quantum fluctuations, and supporting a Quantum Spin Liquid (QSL) state. Long-range quantum entanglement in QSLs prom ...

EPFL2018

Competitive ion-exchange of manganese and gadolinium in titanate nanotubes

László Forró, Bálint Náfrádi, Luka Ciric, Endre Horvath, Péter Szirmai, Márton Kollár

Homogeneous Mn2+ and Gd3+ intercalation of scroll-type trititanate nanotubes using a post-synthesis ion exchange method is reported. Compared to Mn2+, Gd3+ ion-exchange shows larger saturation intercalation levels. Upon co-doping, weak interactions between ...

Elsevier Science Bv2017

Cyan titania nanowires: Spectroscopic study of the origin of the self-doping enhanced photocatalytic activity

László Forró, Richard Gaal, Arnaud Magrez, Alla Arakcheeva, Bálint Náfrádi, Xavier Berdat, Jacim Jacimovic, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard, Péter Szirmai

We report a detailed spectroscopic study of Ti3+ self-doped TiO2 nanowires prepared by high temperature annealing of the protonated titanate nanowires (TiONW) in hydrogen atmosphere. Hydrogenation causes a color change from white to cyan and a major increa ...

Elsevier2017

Upper critical field, pressure-dependent superconductivity and electronic anisotropy of Sm4Fe2As2Te1-xO4-yFy

László Forró, Richard Gaal, Bálint Náfrádi, Sergiy Katrych, Janusz Andrzej Karpinski, Andrea Pisoni, Péter Szirmai

We present a detailed study of the electrical transport properties of a recently discovered iron-based superconductor: Sm4Fe2As2Te0.72O2.8F1.2. We followed the temperature dependence of the upper critical field by resistivity measurement of single crystals ...

Iop Publishing Ltd2016

Magnetotransport studies of superconducting Pr4Fe2As2Te1-xO4

László Forró, Richard Gaal, Bálint Náfrádi, Sergiy Katrych, Janusz Andrzej Karpinski, Andrea Pisoni, Péter Szirmai

We report a study of the electrical transport properties of single crystals of Pr(4)Fe(2)As(2)Te(1-)xO(4), a recently discovered iron-based superconductor. Resistivity, Hall effect, and magnetoresistance are measured in a broad temperature range revealing ...

Amer Physical Soc2016

Anisotropic Elliott-Yafet theory and application to KC8 potassium intercalated graphite

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon, Bence Gábor Márkus

We report electron spin resonance (ESR) measurements on stage-I potassium intercalated graphite (KC8). Angular dependent measurements show that the spin-lattice relaxation time is longer when the magnetic field is perpendicular to the graphene layer as com ...

Wiley-V C H Verlag Gmbh2016

Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I-3

László Forró, Oleg Yazyev, Alla Arakcheeva, Bálint Náfrádi, Massimo Spina, Endre Horvath, Péter Szirmai

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3NH3 ...

Nature Publishing Group2016

Synthesis of Homogeneous Manganese-Doped Titanium Oxide Nanotubes from Titanate Precursors

László Forró, Kurt Schenk, Arnaud Magrez, Bálint Náfrádi, Zlatko Mickovic, Rita Smajda, Endre Horvath, Péter Szirmai

We report a novel synthesis route of homogeneously manganese-doped TiO2 nanotubes in a broad concentration range. The scroll-type trititanate (H2Ti3O7) nanotubes prepared by hydrothermal synthesis were used as precursors. Mn2+ ions were introduced by an io ...

Amer Chemical Soc2013

Observation of conduction electron spin resonance in boron-doped diamond

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon

We observe the electron spin resonance of conduction electrons in boron-doped (6400 ppm) superconducting diamond (T-c = 3.8 K). We clearly identify the benchmarks of conduction electron spin resonance (CESR): the nearly temperature independent electron spi ...

Amer Physical Soc2013