Albert Furrer

TL;DR: An experimental investigation of the excitation spectrum in such a field-induced magnetically ordered state, using inelastic neutron scattering measurements of TlCuCl3 single crystals confirms unambiguously the theoretically predicted gapless Goldstone mode characteristic of the Bose–Einstein condensation of the triplet states.

TL;DR: The continuous emergence in the weakly ordered state of a low-lying but massive excitation corresponding to longitudinal fluctuations of the magnetic moment is demonstrated by neutron spectroscopy.

TL;DR: The oxygen isotope effect on the relaxation rate of crystal-field excitations in the slightly underdoped high-temperature superconductor HoBa2Cu4O8 has been investigated by means of inelastic neutron scattering and shows clear evidence for the opening of an electronic gap in the normal state at T(*) approximately 170 K far above T(c) = 79 K.

TL;DR: The superconductivity is shown to result from the formation of a two-dimensional percolative network in Er 3+ in ErBa 2 Cu 3 O x.

TL;DR: Magnetic clusters, i.e., assemblies of a finite number (between two or three and several hundred) of interacting spin centers which are magnetically decoupled from their environment, can be found in many materials ranging from inorganic compounds, magnetic molecules, artificial metal structures formed on surfaces to metalloproteins as discussed by the authors.