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Bálint Náfrádi

Cette personne a quitté l’EPFL

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Publications associées (79)

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Two-dimensional Magnetism in kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl, a Spin-1/2 Heisenberg Antiferromagnet with Dzyaloshinskii-Moriya Interaction

László Forró, Bálint Náfrádi, Agnes Antal

The finite phase transition temperature, T-N, of quasi two-dimensional (2D) Heisenberg antiferromagnetic (AF) crystals results from in-plane anisotropy or coupling between layers. It is usually not known which is the determining factor when both are weak. ...

Physical Soc Japan2015

Magnetic fluctuations above the Neel temperature in kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl, a quasi-2D Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interaction

László Forró, Bálint Náfrádi, Agnes Antal

We report on magnetic fluctuations studied by electron spin resonance (ESR) spectroscopy in the layered organic crystal ?-(BEDT-TTF)2Cu[N(CN)2]Cl. A line broadening above the antiferromagnetic ordering temperature, TN?=?23?K is attributed to two-dimensiona ...

2012

Possibility of an unconventional spin state of Ir4+ in Ba21Ir9O43 single crystal

László Forró, Henrik Moodysson Rønnow, Oleg Yazyev, Arnaud Magrez, Bálint Náfrádi, Ivica Zivkovic, Alla Arakcheeva, Lin Yang, Andrea Pisoni, Sergiy Katrych, Jacim Jacimovic, Noore Elahi Shaik

We report the synthesis of single crystals of a novel layered iridate Ba21Ir9O43 and present the crystallographic, transport, and magnetic properties of this material. The compound has a hexagonal structure with two iridium oxide layers stacked along the c ...

Amer Physical Soc2016

Controlled growth of CH3NH3PbI3 nanowires in arrays of open nanofluidic channels

László Forró, Bálint Náfrádi, Endre Horvath, Andrzej Sienkiewicz, Massimo Spina

Spatial positioning of nanocrystal building blocks on a solid surface is a prerequisite for assembling individual nanoparticles into functional devices. Here, we report on the graphoepitaxial liquid-solid growth of nanowires of the photovoltaic compound CH ...

Nature Research2016

Competitive ion-exchange of manganese and gadolinium in titanate nanotubes

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

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

Photodiode Response in a CH3NH3PbI3/CH3NH3SnI3 Heterojunction

László Forró, Bálint Náfrádi, Endre Horvath, Massimo Spina, Andrea Pisoni

Here we report another surprising feature of the methylammonium metal halide material family, the phototunability of the diode response of a heterojunction made of CH3NH3PbI3 and its close relative, CH3NH3SnI3. In the dark state the device behaves as a dio ...

2017

Improved Alkali Intercalation of Carbonaceous Materials in Ammonia Solution

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon

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

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

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon

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

Spin resonance in the ordered magnetic state of Ni-5(TeO3)(4)Cl-2

László Forró, Helmuth Berger, Bálint Náfrádi

The transition metal tellurium oxychloride, Ni-5(TeO3)(4)Cl-2, has been investigated by high-field electron-spin resonance for frequencies up to 3 THz, at temperatures well below the magnetic ordering at 23 K. At zero external field several resonance modes ...

2006

Three-Dimensionally Enlarged Photoelectrodes by a Protogenetic Inclusion of Vertically Aligned Carbon Nanotubes into CH3NH3PbBr3 Single Crystals

László Forró, Andrzej Sienkiewicz, Bálint Náfrádi, Endre Horvath, Márton Kollár, Pavao Roko Andricevic, Xavier François Mettan, Dóra Fejes-Kajtár

We demonstrate that single crystals of methylammonium lead bromide (MAPbBr(3)) could be grown directly on vertically aligned carbon nanotube (VACNT) forests. The fast-growing MAPbBr3 single crystals engulfed the protogenetic inclusions in the form of indiv ...

2017

Dry-pressed anodized titania nanotube/CH3NH3PbI3 single crystal heterojunctions: The beneficial role of N doping

László Forró, Bálint Náfrádi, Endre Horvath, Konrad Domanski, Márton Kollár, Pavao Roko Andricevic

Highly ordered, anodically grown TiO2 nanotubes on titanium supports were annealed in ammonia atmosphere in order to incorporate nitrogen doping (

2019

Continuous-wave far-infrared ESR spectrometer for high-pressure measurements

László Forró, Andrzej Sienkiewicz, Bálint Náfrádi, Richard Gaal

We present a newly-developed microwave probe for performing sensitive high-field/multi-frequency electron spin resonance (ESR) measurements under high hydrostatic pressures. The system consists of a BeCu-made pressure-resistant vessel, which accommodates t ...

Academic Press Inc - Elsevier Science2008

Room temperature manipulation of long lifetime spins in metallic-like carbon nanospheres

László Forró, Bálint Náfrádi

The time-window for processing electron spin information (spintronics) in solid-state quantum electronic devices is determined by the spin-lattice and spin-spin relaxation times of electrons. Minimizing the effects of spin-orbit coupling and the local magn ...

Nature Publishing Group2016

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

László Forró, Andrzej Sienkiewicz, Bálint Náfrádi, Endre Horvath, Márton Kollár, Philippe Bugnon, Péter Szirmai, Pavao Roko Andricevic, Lidia Rocoffort de Vinnière, Anastasiia Glushkova, 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

Methylammonium Lead Iodide for Efficient X-ray Energy Conversion

László Forró, Endre Horvath, Bálint Náfrádi

We report on photocurrent generation by X-ray irradiation in methylammonium lead iodide CH3NH3PbI3 single crystals. We observed 75% of charge collection efficiency in millimeter sized samples. This efficiency is partially due to the high photon absorption ...

American Chemical Society2015

Evolution of two-dimensional antiferromagnetism with temperature and magnetic field in multiferroic Ba2CoGe2O7

Bálint Náfrádi

We report on spherical neutron polarimetry and unpolarized neutron diffraction in zero magnetic field as well as flipping ratio and static magnetization measurements in high magnetic fields on the multiferroic square lattice antiferromagnet Ba2CoGe2O7. We ...

Amer Physical Soc2014

Electron Spin Dynamics of Two-Dimensional Layered Materials

László Forró, Bálint Náfrádi

The growing library of two-dimensional layered materials is providing researchers with a wealth of opportunity to explore and tune physical phenomena at the nanoscale. Here, we review the experimental and theoretical state-of-art concerning the electron sp ...

Wiley-V C H Verlag Gmbh2017

Clean, cleaved surfaces of the photovoltaic perovskite

László Forró, Henrik Moodysson Rønnow, Jeremy Luterbacher, Bálint Náfrádi, Endre Horvath, Jan Hugo Dil, Stefan Peter Muff, Andrew Patton Weber, Márton Kollár, Luka Ciric, Benjamin Pierre Le Monnier

The surface of a material is not only a window into its bulk physical properties, but also hosts unique phenomena important for understanding the properties of a solid as a whole. Surface sensitive techniques, like ARPES (Angle-resolved photoemission spect ...

Nature Research2017

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

László Forró, Bálint Náfrádi, Péter Szirmai, Ferenc Simon

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

Topological Analysis of the Experimental Electron Density in Multiferroic Antiferromagnet Ba2MnGe2O7

Bálint Náfrádi

In the field of magnetoelectric coupling, especially via the spin-dependent metal-ligand d-p hybridization mechanism found in multiferroic Ba2MGe2O7 (M = Mn, Co), detailed knowledge of the microscopic structural parameters is essential, also for the theore ...

Institute of Electrical and Electronics Engineers2022