Phase stability study of La1.2Ca1.8Mn2O7

Abstract We report that the composition of La 1.2 Ca 1.8 Mn 2 O 7 does not form as a single phase, and consists of a mixture of La 0.6 Ca 0.4 MnO 3 and CaO. The XRD patterns show the presence of a peak at 2θ ∼ 37°, which is a specific peak to indicate the existence of CaO with space group Fm 3 m and a unit cell of a = 4.8152(3) A. After a few days, the intensity of this peak decreases and CaO transforms to Ca(OH) 2 . The electrical and magnetic measurements show that the colossal magnetoresistance (CMR) behavior corresponds to that exhibited by La 0.6 Ca 0.4 MnO 3 .