The correlation between structure and magnetic properties in the manganites La 0.7Ca 0.3− xTe xMnO 3 (0≤ x≤0.15)

Abstract

The effect of Te-doping at La-site on structural, magnetic and transport properties in the manganites La 0.7Ca 0.3− x Te x MnO 3 (0≤ x≤0.15) has been investigated. All samples show an orthorhombic structure ( O′- Pbnm) at room temperature. It shows that the Mn–O–Mn bond angle decreases and the Mn–O bond length increases with the increase in the Te content. All samples exhibit an insulator–metal (I–M) transition and the resistivity increases with the increase in the Te-doping level. Additionally, the Curie temperature T c decreases and the transition becomes broader with increasing Te-doping level, in contrast, the magnetization of Te-doping samples at low temperatures decrease with increasing x as x≤0.10 and then increase with further increasing x to 0.15. The results are discussed in terms of Jahn–Teller (JT) vibrational anisotropy Q 3/ Q 2 and the opening of the new DE channel between Mn 2+–O–Mn 3+ due to the introduction of Mn 2+ ions because of the substitution of Te 4+ ions for Ca 2+ ions.