Muon spin relaxation study of magnetic cluster glass formation accompanying suppression of ferromagnetic order in Sr1-x(La0.5K0.5)xRuO3

Sr1-x(La0.5K0.5)xRuO3 is a substitutional magnetic system, in which ferromagnetic (FM) order originating from itinerant Ru 4d electrons is suppressed by increasing the dopant concentration x and disappears at the critical concentration x = 0.5. Recently, we have performed a detailed magnetic and thermal experiment and found that the FM ordered state changes to a cluster-glass state, before reaching the critical concentration, and therefore, no prominent feature ascribed to the FM quantum critical fluctuations was observed in thermodynamic measurements. The formation of the cluster-glass state seems to markedly affect to the electronic properties of Sr1-x(La0.5K0.5)xRuO3 at around the critical concentration. In this study, we propose to perform zero-field and longitudinal muSR experiments to study the microscopic details of the cluster glass state and the dynamics of magnetic clusters.