Publications de Julian Piatek | EPFL Graph Search

Electronic transport and magnetism in the alternating stack of metallic and highly frustrated magnetic layers in Co(1/3)NbS(2)

Helmuth Berger, László Forró, Julian Piatek, Henrik Moodysson Rønnow, Ivica Zivkovic, Jacim Jacimovic, Nikolay Tsyrulin

Transition-metal dichalcogenides (TMDs) are layered compounds that support many electronic phases, including various charge density waves, superconducting, and Mott insulating states. Their intercalation with magnetic ions introduces magnetic sublayers, wh ...

AMER PHYSICAL SOC2023

Phase diagram of diluted Ising ferromagnet LiHoxY1-xF4

Conradin Kraemer, Bastien Dalla Piazza, Julian Piatek, Henrik Moodysson Rønnow, Neda Nikseresht Ghanepour, Ivan Kovacevic, Peter Babkevich

We present a systematic study of the phase diagram of LiHoxY1-xF4 (0.25

Amer Physical Soc2016

Probing strongly hybridized nuclear-electronic states in a model quantum ferromagnet

Giovanni Boero, Julian Piatek, Henrik Moodysson Rønnow, Ivan Kovacevic, Peter Babkevich

We present direct local-probe evidence for strongly hybridized nuclear-electronic spin states of an Ising ferromagnet LiHoF4 in a transverse magnetic field. The nuclear-electronic states are addressed via a magnetic resonance in the GHz frequency range usi ...

2016

An ultra-low temperature scanning Hall probe microscope for magnetic imaging below 40 mK

Julian Piatek, Henrik Moodysson Rønnow

We describe the design of a low temperature scanning Hall probe microscope (SHPM) for a dilution refrigerator system. A detachable SHPM head with 25.4 mm OD and 200 mm length is integrated at the end of the mixing chamber base plate of the dilution refrige ...

American Institute of Physics2014

Nonequilibrium hysteresis and spin relaxation in the mixed-anisotropy dipolar-coupled spin-glass LiHo0.5Er0.5F4

Bastien Dalla Piazza, Julian Piatek, Stephen Paul Neithardt, Henrik Moodysson Rønnow, Ivan Kovacevic, Peter Babkevich

We present a study of the model spin-glass LiHo0.5Er0.5F4 using simultaneous ac susceptibility, magnetization, and magnetocaloric effect measurements along with small angle neutron scattering ( SANS) at sub-Kelvin temperatures. All measured bulk quantities ...

American Physical Society2014

Glassy dynamics in the low-temperature inhomogeneous ferromagnetic phase of the quantum spin ice Yb2Sn2O7

Julian Piatek, Ivica Zivkovic

Here we present a detailed muon spin relaxation (mu SR), neutron diffraction, and ac-susceptibility study of Yb2Sn2O7 that shows that despite the onset of ferromagnetic long-range order at T-c approximate to 0.140 K, the low-temperature phase of this mater ...

Amer Physical Soc2014

Low-temperature spin dynamics of a valence bond glass in Ba2YMoO6

Julian Piatek, Henrik Moodysson Rønnow

We carried out ac magnetic susceptibility measurements and muon spin relaxation spectroscopy on the cubic double perovskite Ba2YMoO6, down to 50 mK. Below similar to 1 K the muon relaxation is typical of a magnetic insulator with a spin-liquid type ground ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2013

Electronic structure of KTi(SO4)(2)center dot H2O: An S=1/2 frustrated chain antiferromagnet

Julian Piatek, Henrik Moodysson Rønnow, Goran Nilsen

The compound KTi(SO4)(2)center dot H2O was recently reported as a quasi-one-dimensional spin-1/2 compound with competing antiferromagnetic nearest-neighbor exchange J(1) and next-nearest-neighbor exchange J(2) along the chain with a frustration ratio alpha ...

American Physical Society2013

Phase diagram with an enhanced spin-glass region of the mixed Ising–XY magnet LiHoxEr1-xF4

Bastien Dalla Piazza, Julian Piatek, Henrik Moodysson Rønnow, Ivica Zivkovic, Neda Nikseresht Ghanepour, Nikolay Tsyrulin

We present the experimental phase diagram of LiHoxEr1-xF4, a dilution series of dipolar-coupled model magnets. The phase diagram was determined using a combination of ac susceptibility and neutron scattering. Three unique phases in addition to the Ising fe ...

Amer Physical Soc2013

Dipolar Antiferromagnetism and Quantum Criticality in LiErF4

Conradin Kraemer, Bastien Dalla Piazza, Julian Piatek, Henrik Moodysson Rønnow, Neda Nikseresht Ghanepour, Nikolay Tsyrulin, Gabriel Aeppli

Magnetism has been predicted to occur in systems in which dipolar interactions dominate exchange. We present neutron scattering, specific heat, and magnetic susceptibility data for LiErF4, establishing it as a model dipolar-coupled antiferromagnet with pla ...

American Association for the Advancement of Science2012

Ultra Low Temperature Susceptometer and Magnetometer : Study of the Spin Glass Series LiHox Er1-x F4

Julian Piatek

The first part of this thesis discusses technical details relating to measurements of magnetic properties at ultra low temperatures. The implementation of AC susceptibility at temperatures down to 30 mK is introduced and used as a platform to showcase sele ...

EPFL2012

Spangolite: an s = 1/2 maple leaf lattice antiferromagnet?

Julian Piatek, Henrik Moodysson Rønnow, Goran Nilsen

Spangolite, Cu6Al(SO4)(OH)12Cl·3H2O, is a hydrated layered copper sulfate mineral. The Cu2+ ions of each layer form a systematically depleted triangular lattice which approximates a maple leaf lattice. We present details of the crystal structure, which sug ...

2011

Superconducting phase in the layered dichalcogenide 1T-TaS_{2} upon inhibition of the metal-insulator transition

Helmuth Berger, László Forró, Marco Grioni, Balazs Sipos, Julian Piatek, Ping-Hui Lin, Peng Xu, Henrik Moodysson Rønnow

When a Mott metal-insulator transition is inhibited by a small amount of disorder in the layered dichalcogenide 1T-TaS2, an inhomogeneous superconducting state arises below T=2.1 K and coexists with a nearly commensurate charge-density wave. By angle-resol ...

2010

Scale-Free Antiferromagnetic Fluctuations in the s=1/2 Kagome Antiferromagnet Herbertsmithite

Julian Piatek, Henrik Moodysson Rønnow, Goran Nilsen

Neutron spectroscopy and diffuse neutron scattering on herbertsmithite [ZnCu3(OH)(6)Cl-2], a near-ideal realization of the s=1/2 kagome antiferromagnet, reveal the hallmark property of a quantum spin liquid: instantaneous short-ranged antiferromagnetic cor ...

2009