Abstract
Elastic and inelastic neutron scattering experiments have been performed on the dimer spin system , which shows plateaus in the magnetization curve at and of the saturation value. Two structural phase transitions at and at lead to a doubling of the crystallographic unit cell along the direction and as a consequence a segregation into different dimer subsystems. Long-range magnetic ordering is reported below . The magnetic field dependence of the excitation spectrum identifies successive quantum phase transitions of the dimer subsystems as the driving mechanism for the unconventional magnetization process in agreement with a recent theoretical model.
- Received 27 April 2004
DOI:https://doi.org/10.1103/PhysRevLett.93.037207
©2004 American Physical Society