Field Induced Lattice Deformation in the Quantum Antiferromagnet SrCu<SUB>2</SUB>(BO<SUB>3</SUB>)<SUB>2</SUB>
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The results of synchrotron X-ray diffraction by the coupled dimer compound SrCu<SUB>2</SUB>(BO<SUB>3</SUB>)<SUB>2</SUB> subjected to a pulsed high magnetic field are reported. We find the lattice constant, <I>a</I>, contracts with increasing magnetic field. This change in the lattice constant scales with the magnetization change. We argue that the nearest neighbor exchange interaction between Cu<SUP>2+</SUP> spins is an antiferromagnetic one through an oxygen and its strength depends on the bond angle Cu<SUP>2+</SUP>–O<SUP>2−</SUP>–Cu<SUP>2+</SUP>. The bond length between the Cu ions in a triplet becomes shorter to make the bond angle smaller and to diminish the antiferromagnetic exchange interaction. We propose this mechanism as a main source of the lattice contraction.
- Journal of the Physical Society of Japan
Journal of the Physical Society of Japan 78(4), 043702-043702, 2009
THE PHYSICAL SOCIETY OF JAPAN