2020/11/13 by Michael Dettbarn, Dettbarn, Michael, V. B. Zabolotnyy +13
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic Properties of Alloys #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2011.07108
openalex publication_date 2020/11/13 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
At room temperature, bulk La7/8Sr1/8MnO3 is in the dynamic\nJahn--Teller O^* phase, but undergoes a transition to a static, magnetically\nordered Jahn--Teller phase at lower temperatures. Here we study a 6 unit\ncells thin film of this compound grown on SrTiO3, resulting in small\ncompressive strain due to a lattice mismatch of lesssim 0.2 %. We combine\nX-ray absorption spectroscopy with multiplet ligand field theory to study the\nlocal electronic and magnetic properties of Mn in the film. We determine the Mn\nd3z2-r2 orbital to be 0.13 ;\eV lower in energy than the\ndx2-y2, which is a disproportionately large splitting given the small\ndegree of compressive strain. We interpret this as resulting from the strain\nproviding a preferential orientation for the MnO6 octahedra, which are\nstrongly susceptible to such a deformation in the vicinity of the phase\ntransition. Hence, they collectively elongate along the c axis into a static\nJahn--Teller arrangement. Furthermore, we demonstrate the strongly covalent\ncharacter of La7/8Sr1/8MnO3, with a contribution of nearly 50 %\nof the one-ligand-hole configuration d5 underlineL1 to the ground\nstate wavefunction. Finally, we find the system to be in a high-spin\nconfiguration, with the projection of the local magnetic moment on the\nquantization axis being about 3.7 ;\μ\B/\Mn. We show,\nhowever, that the system is close to a high-spin--low-spin transition, which\nmight be triggered by crystal field effects.\n