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D. Huvonen

Publications and source records attributed to D. Huvonen.

3 recordsLinked to original sources
arXiv2013

Criticality in a disordered quantum antiferromagnet by neutron diffraction

Field-induced magnetic ordering in the structurally disordered quantum magnets Ni(Cl$_{1-x}$Br$_x$)$_2$$\cdot$4SC(NH$_2$)$_2$, $x=8$% and 13%, is studied by means of neutron diffraction. The order parameter critical exponent is found to be very close to its value $β=0.5$ expected for magnetic Bose-Einstein condensation in the absence of disorder. This result applies to temperatures down to 40 mK, and a 1 T range in magnetic field. The crossover exponent is found to be $ϕ\sim 0.4$, for temperature ranges as small as 300 mK. Possible reasons for a discrepancy with recent numerical simulations and bulk measurements are discussed.

cond-mat.str-el↗
arXiv2012

Excitations in a quantum spin liquid with random bonds

We present results of inelastic neutron scattering study on two bond disordered quasi twodimensional quantum magnets (C$_4$H$_12$N$_2$)Cu$_2$(Cl$_{1-x}$Br$_x$)$_6$ with x=0.035 and 0.075. We observe the increase of spin gap, reduction of magnon bandwidth and a decrease of magnon lifetimes compared to x=0 sample. Additional magnon damping is observed at higher energies away from zone center which is found to follow the density of single particle states.

cond-mat.str-el↗
arXiv2011

Crystals for neutron scattering studies of quantum magnetism

We review a strategy for targeted synthesis of large single crystal samples of prototype quantum magnets for inelastic neutron scattering experiments. Four case studies of organic copper halogenide S=1/2 systems are presented. They are meant to illustrate that exciting experimental results pertaining to forefront many-body quantum physics can be obtained on samples grown using very simple techniques, standard laboratory equipment, and almost no experience in in advanced crystal growth techniques.

cond-mat.str-el↗