Abstract
The magnetic phase transition under hydrostatic pressure in was investigated by magnetization measurements. The parent compound is a coupled-spin-dimer system, which undergoes a pressure-induced quantum phase transition from a gapped ground state to an antiferromagnetic state at due to the shrinkage of the gap. At ambient pressure, the present doped system exhibits impurity-induced magnetic ordering at . With increasing pressure, increases. This is because the effective exchange interaction between unpaired spins is enhanced by the shrinkage of the gap. With a further increase in pressure, the present system undergoes a phase transition to a uniform antiferromagnetic phase due to the closing of the triplet gap in the intact dimers. The crossover from the impurity-induced ordered phase to the uniform antiferromagnetic phase occurs at .
3 More- Received 17 May 2006
DOI:https://doi.org/10.1103/PhysRevB.74.064423
©2006 American Physical Society