Magnetic and neutron diffraction study on perovskites La1-xSrxCrO3

Magnetic properties of perovskite-type compounds La1-xSrx CrO3 (x = 0, 0.05 , 0.10, 0.15, 0.20, and 0.25) have been reported. Their DC magnetic suscept ibilities were measured from 4.5 K to 320 K. All these compounds showed an antiferromagnetic transition and their Neel temperatures decreased linearly from 286 K for LaCrO3 with increasing Sr substitution. Below the Ni el tem peratures, other two magnetic transitions were furthermore observed for alm ost all the compounds. Below the Neel temperatures, all the compounds excep t LaCrO3 showed magnetic hysteresis, The initial magnetization curve indica tes the existence of the metamagnetic property below 20 ii, Powder neutron measurements were performed at room temperature, 250 K and 50 K for La0.85S r0.15 CrO3. It was found that the crystal phase and magnetic transition occ urred between 50 It and 250 K. The crystal structure at 250 K is rhombohedr al with space group R (3) over bar c, and it transforms to an orthorhombic structure with space group Pnma at 50 K. The magnetic structures at 50 K an d at 250 K are both the C-type. The direction of magnetic moments is direct ed to [111] of the rhombohedral unit cell at 250 K and changes to be parall el to the z-axis of the orthorhombic unit cell (Pnma) at 50 K. (C) 1998 Aca demic Press.