Chaluvadi Sandeep Kumar, Polewczyk Vincent, Petrov Aleksandr Yu, Vinai Giovanni, Braglia Luca, Diez Jose Manuel, Pierron Victor, Perna Paolo, Mechin Laurence, Torelli Piero, Orgiani Pasquale
Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park, S.S.14, km 163.5, I-34149 Trieste, Italy.
IMDEA-Nanociencia, Campus de Cantoblanco, 28049 Madrid, Spain.
ACS Omega. 2022 Apr 20;7(17):14571-14578. doi: 10.1021/acsomega.1c06529. eCollection 2022 May 3.
The structural, electronic, and magnetic properties of Sr-hole-doped epitaxial La Sr MnO (0.15 ≤ ≤ 0.45) thin films deposited using the molecular beam epitaxy technique on 4° vicinal STO (001) substrates are probed by the combination of X-ray diffraction and various synchrotron-based spectroscopy techniques. The structural characterizations evidence a significant shift in the LSMO (002) peak to the higher diffraction angles owing to the increase in Sr doping concentrations in thin films. The nature of the LSMO Mn mixed-valence state was estimated from X-ray photoemission spectroscopy together with the relative changes in the Mn L edges observed in X-ray absorption spectroscopy (XAS), both strongly affected by doping. CTM4XAS simulations at the XAS Mn L edges reveal the combination of epitaxial strain, and different MnO crystal field splitting give rise to a peak at ∼641 eV. The observed changes in the occupancy of the e and the t orbitals as well as their binding energy positions toward the Fermi level with hole doping are discussed. The room-temperature magnetic properties were probed at the end by circular dichroism.
利用分子束外延技术在4°斜切的STO(001)衬底上沉积的Sr空穴掺杂外延LaSrMnO(0.15≤≤0.45)薄膜的结构、电子和磁性,通过X射线衍射和各种基于同步加速器的光谱技术相结合进行探测。结构表征表明,由于薄膜中Sr掺杂浓度的增加,LSMO(002)峰显著向更高衍射角移动。通过X射线光电子能谱以及在X射线吸收光谱(XAS)中观察到的Mn L边的相对变化来估计LSMO Mn混合价态的性质,两者都受到掺杂的强烈影响。XAS Mn L边的CTM4XAS模拟表明,外延应变和不同的MnO晶体场分裂相结合,在约641 eV处产生一个峰。讨论了观察到的随着空穴掺杂,e和t轨道占有率及其相对于费米能级的结合能位置的变化。最后通过圆二色性探测了室温磁性。