루테네이트 양자 이합체 시스템에 관한 자성 연구

Abstract

Quantum Dimer Magnet has become attracting issue in current research because of its exotic behavior related with correlated system in solid systems. Recently, Terasaki et al measured no long range order on Ba3ZnRu2O9 down to 37mK, where neither Curie tail nor glassy behavior is detected. This material also shows unexpected magnetic moment at 4.2 K measured by 99-Ru Mossbauer experiment. In this report, we compare two Ruthenate system experimentally; Ba5Ru2O10, which has wide interdimer dictance sufficient to consider as isolated spin dimer system, with Ba3ZnRu2O9, which can’t be explained by simple dimer model due to the narrow interdimer distance as we assumed. We performed EDS, XRD experiment to confirm these materials were synthesized as expected. In the case of Ba5Ru2O10, magnetic properties meassured by VSM shows conventional dimerized spin system. Temperature dependence of susceptibility data follows theoretical dimer model assumed isolated, two 3/2 spin system. In the case of Ba3ZnRu2O9, magnetic properties does not follow conventional dimerized spin system, so we extract residual susceptibility from pure 3/2 dimer susceptibility by delicate fitting procedure using constant parameter added dimer model. Magnetic field dependence of magnetization also shows different behavior compared with conventional dimer system. We propose Inelastic Neutron Scattering experiment would reveal this residual susceptibility might related with interdimer correlation energy.