Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6114, USA.
J Phys Condens Matter. 2010 Apr 14;22(14):146007. doi: 10.1088/0953-8984/22/14/146007. Epub 2010 Mar 23.
The magnetic, structural, and transport properties of pulsed-laser deposited LaMnO(3) thin films are analyzed as a function of the O(2) partial pressure in the growth environment (using an O(2)/Ar gas mixture). Interestingly, the magnetic properties do not change gradually as the O(2) content increases. Instead, ferromagnetism emerges rapidly with the oxygen; a critical amount of Ar is needed to suppress ferromagnetism effectively in LaMnO(3) thin films. The most dramatic suppression of ferromagnetism occurs only in the narrow window below 10% oxygen, where the ferromagnetic moments decrease by a factor of 17. Above a certain oxygen concentration, the ferromagnetic moment no longer increases with oxygen. The sample grown in pure oxygen shows a metal-insulator transition at ∼200 K, but exhibits an insulating behavior again below ∼150 K. This intermediate metallic behavior is significantly suppressed by using the O(2)/Ar gas mixture.
脉冲激光沉积 LaMnO(3) 薄膜的磁性、结构和输运性质随生长环境中的 O(2)分压（使用 O(2)/Ar 混合气体）而变化。有趣的是，磁性并不会随着 O(2)含量的增加而逐渐变化。相反，随着氧气的增加，铁磁性迅速出现；在 LaMnO(3)薄膜中，需要一定量的 Ar 才能有效地抑制铁磁性。铁磁性的最大抑制仅发生在氧气含量低于 10%的狭窄窗口内，其中铁磁矩减小了 17 倍。在某个氧气浓度以上，铁磁矩不再随氧气而增加。在纯氧中生长的样品在约 200 K 处显示出金属-绝缘体转变，但在约 150 K 以下再次表现出绝缘行为。这种中间金属行为通过使用 O(2)/Ar 混合气体得到了显著抑制。
