MAGNETIC EXCITATIONS IN THE S=1/2 QUASI-ONE-DIMENSIONAL MAGNET SR14-XCAXCU24O41

Neutron scattering experiments have been performed on Sr14−xCaxCu24O41 (x=3 and 6), which consists of CuO2 chains and Cu2O3 ladders, in order to study the effect of Ca substitution on the dimerized state in the chains. The Ca substitution broadens the excitation peak although the excitation energy is almost unchanged. The effects of Ca and Y substitution on the dimerized state are compared.