Competitions between magnetic interactions in the ground states are typically the driving forces of unexpected electronic phenomena of a magnetic system. Manganese oxides with the AMnO3 (A = La, Sr, etc.) perovskite structure are examples of these materials. They are often strongly correlated electron systems in which the interplay between spin, charge, orbital, and lattice degrees of freedom play a crucial role in determining their physical properties. Through the variation of the Mn-O-Mn bond angle and the oxidation state of Mn ions between 3+ and 4+, these manganites display various ground states, such as anti-ferromagnetic charge/orbital-ordered insulator or ferromagnetic metal. Using resonant soft X-ray scattering, we revealed the magnetic properties of 15R-BaMnO3-x, which is expected to exhibit interesting multiferroic features. Our results of magnetic scattering provide evidence for the magnetic structure and transition of this system. Results of X-ray magnetic scattering do not depend on X-ray helicities; the magnetic structure of 15R-BaMnO3 is not spiral, unlike a spiral hexaferrite, Ba0.5Sr1.5Zn2Fe12O22.
在磁性材料中,磁性基態的交互競爭是決定電子特性的主要因素。擁有鈣鈦礦結構的錳氧化物材料AMnO3 (A = La, Sr, etc.) 就是很好的例子;這類強關聯電子材料中,電子的電荷、自旋、軌域與晶體結構強烈的交互作用,並扮演著決定這些材料物理性質的關鍵角色。舉例來說,經由錳-氧-錳的鍵結角度及錳三價與錳四價氧化態的變化,這些錳氧化物可以表現出很多不同的磁性基態,如反鐵磁、電荷有序與軌域有序的絕緣體或鐵磁的導體以及多鐵現象;所以這類材料的磁性結構是很有趣的。 為了瞭解這類材料有趣的磁性結構,我們藉由軟X光共振散射實驗,探討一個預期擁有多鐵性質的15R-BaMnO3-x之磁性性質,了解其磁性結構與磁相變。進一步,我們利用不同旋光性的共振磁散射實驗,確認15R-BaMnO3-x並不具有螺旋狀的磁性結構。