Magnetic Behaviour Of Fe Substituted Bilayered Manganite La(1.2)Sr(1.5)Ca(0.3)Mn(2)O(7)

For studying the effect of low level substitution of Fe (at Mn site) on magnetic behaviour in the bilayered system La(1.2)Sr(1.5)Ca(0.3)Mn(2)O(7), dc magnetization measurements have been made on La(1.2)Sr(1.5)Ca(0.3)Mn(1.99)Fe(0.01)O(7). Cooling from 300K downwards, the system shows transition to ferromagnetic (FM) ordering in ab plane (at similar to 250K), to antiferromagnetic state (at similar to 195K) and to 3D FM order (at similar to 70K). Magnetization - temperature measurements in zero field cooling and field cooling modes, made under different external magnetic fields, and the observed long time evolution of magnetization with time, are suggestive of FM disorder and high magnetic anisotropy. Substitution of Fe weakens ferromagnetism.