Effect of strain on magnetic and orbital ordering of LaSrCrO3/LaSrMnO3 heterostructures

Abstract

We investigate the effect of strain and film thickness on the orbital and magnetic properties of LaSrCrO 3 (LSCO)/LaSrMnO 3 (LSMO) heterostructures using bulk magnetometry, soft Xray magnetic spectroscopy, first-principles density functional theory, high-resolution electron microscopy and X-ray diffraction. We observe an anti-parallel ordering of the magnetic moments between the ferromagnetic LSMO layers and the LSCO spacers leading to a strain-independent ferromagnetic ground state of the LSCO/LSMO heterostructures for LSMO layers as thin as 2 unit cells. As the LSMO thickness is increased, a net ferromagnetic state is maintained, however, the average magnetic moment per Mn is found to be dependent on the magnitude of the substrateinduced strain. The differences in the magnetic responses are related to preferential occupation of the Mn x 2 −y 2 (in-plane) d-orbitals for tensile strain and 3z 2 −r 2 (out-of-plane) orbitals under compressive strain leading to competing ferromagnetic and anti-ferromagnetic exchange interactions within the LSMO layers. These results underscore the relative contributions of orbital, structural and spin degree of freedom and their tunability in atomically-thin crystalline complex oxide layers.

Electronic, Orbital, and Spin Reconstructions at the Interface between Metallic La0.7Sr0.3MnO3 and Charge-Disproportionated Insulator SrCoO2.5

“…The calculated in-plane lattice parameter of the SCO layer is 3.868 Å, the same as that of the LSAT substrate, which further confirms the strained nature of the SCO layer in both the single-layer film and the heterostructure. On the other hand, the lattice parameter of LSMO in the cubic notation is 3.875 Å, 11 slightly greater than that of the LSAT substrate, and therefore, is buried under the reflections of the latter. Besides, the thickness of the LSMO layers is only 9 uc, which is close to 3.5 nm, and therefore it would be hard to detect from the labbased diffractometer.…”

Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

“…This would then decrease the hopping transport probability and consequently decrease the mobile hole density responsible for p-type electrical (semi)­conductivity by small polaron hopping. Additionally, a Jahn–Teller-like distortion may occur as observed in CrO 2 or other perovskite oxides such as La 2/3 Sr 1/3 MnO 3 , , LaCoO 3 , and SrVO 3 , where in-plane tensile strain would lower and favor the occupied in-plane Cr 3d t 2g ( xy ) orbital ground state (Figure ). On the contrary, the biaxial in-plane compressive strain (smaller Cr–O bond length, ⟨Cr–O–Cr⟩ bond angle than 162°, and unit-cell volume) would increase the Cr 3d–O 2p orbital hybridization (bandwidth) and/or lower the occupied out-of-plane Cr 3d t 2g ( xz and yz ) orbitals that would tend to be more delocalized and increase the hopping transport probability (Figure ).…”

“…This would then decrease the hopping transport probability and consequently decrease the mobile hole density responsible for p-type electrical (semi)conductivity by small polaron hopping. Additionally, a Jahn-Teller like distortion may occur as observed in CrO2 67 or other perovskite oxides such as La2/3Sr1/3MnO3 39,68 , LaCoO3 41 and SrVO3 19 where in-plane tensile strain would lower and favor the occupied in-plane Cr 3d t2g (xy) orbital ground state (Figure 6).…”

Trigonal Symmetry Breaking and its Electronic Effects in Two-Dimensional Dihalides and Trihalides

“…Transition metal compounds exhibit electronic properties of high scientific and technological interest, including ferroelectricity [1][2][3][4], quantum magnetism [5][6][7][8][9][10], metal-insulator transitions [11][12][13][14][15][16][17][18][19][20][21] , and high transitiontemperature superconductivity [22][23][24][25][26]. Transition metal oxides derived from the AMO 3 perovskite structure have been a focus of particular attention because any 3d or 4d transition metal can occupy the M site with (typically) partially filled d shells, while variation of the A-site ion can tune the relative valence of the M site ion and the electronic bandwidth.…”