Exploiting symmetry-mismatch to control magnetism in a ferroelastic heterostructure

Abstract

In the bulk, LaCoO3 (LCO) is a paramagnet, yet in tensile strained thin films at low temperature ferromagnetism (FM) is observed, and its origin remains unresolved. Polarized neutron reflectometry (PNR) is a powerful tool to determine the depth profiles of the structure and magnetization simultaneously and thus the evolution of the interfacial FM with strain can be accurately revealed. Here we quantitatively measured the distribution of atomic density and magnetization in LCO films by PNR and found that the LCO layers near the heterointerfaces exhibit a reduced magnetization but an enhanced atomic density, whereas the interior shows the opposite trend. We attribute the nonuniformity to the symmetry mismatch at the interface, which induces a structural distortion related to the ferroelasticity of LCO. This assertion is tested by systematic application of hydrostatic pressure during the PNR experiments. These results provide unique insights into mechanisms driving FM in strained LCO films while offering a tantalizing observation that tunable deformation of the CoO6 octahedra in combination with the ferroelastic order parameter.

arXiv comment17 pages, 4 figures, and one supporting information

References in corpus (9)

• The spin state transition in LaCoO${}_3$; revising a revision
• Structural phenomena associated with the spin-state transition in LaCoO3
• Evidence for orbital ordering in LaCoO3
• Spin-state transition in LaCoO3: direct neutron spectroscopic evidence of excited magnetic states
• Pressure-Induced Intermediate-to-Low Spin State Transition in LaCoO3
• Temperature and pressure-induced spin-state transitions in LaCoO3
• Strain-Induced Spin States in Atomically Ordered Cobaltites
• Reversible strain effect on the magnetization of LaCoO3 films
• Suppression of spin-state transition in epitaxially strained LaCoO_{3}

Cited by in corpus (7)

• Strain-induced atomic-scale building blocks for ferromagnetism in epitaxial LaCoO3
• Dynamics of anisotropic oxygen-ion migration in strained cobaltites
• Spin State Disproportionation in Insulating Ferromagnetic LaCoO3 Epitaxial Thin Films
• Tunable Ferromagnetism in LaCoO3 Epitaxial Thin Films
• Room-Temperature Valence Transition in a Strain-Tuned Perovskite Oxide
• Visualizing quantum phenomena at complex oxide interfaces: an atomic view from scanning transmission electron microscopy
• Atomic-scale Modulation of Synthetic Magnetic Order in Oxide Superlattices