Static Magnetic Order in A-site Ordered Perovskite, LaCu3Cr4O12, Probed with Muon Spin Spectroscopy

The microscopic magnetic nature of a novel A-site ordered chromium perovskite, LaCu3Cr4O12, has been studied with muon spin rotation and relaxation (μ+SR) measurements down to 2 K using a powder sample. Magnetization and resistivity measurements indicated the presence of a magnetic transition at TM = 225 K together with a metal-to-metal transition. Moreover, since the magnetization versus temperature curve showed a step-like decrease at TM with de- creasing temperature, LaCu3Cr4O12 was thought to enter into a spin-singlet like state below TM. However, μ+SR together with magnetization measurements demonstrate the appearance of static antiferromagnetic (AF) order below TM, i.e. TM = TN. Furthermore, the AF order was assigned to be incommensurate (IC) to the lattice and such IC-AF phase was most likely to change to a commensurate-AF phase below 25 K.