Thickness-dependent ferromagnetic metal to paramagnetic insulator transition in La${}_{0.6}$Sr${}_{0.4}$MnO${}_3$ thin films studied by x-ray magnetic circular dichroism

Abstract

Metallic transition-metal oxides undergo a metal-to-insulator transition (MIT) as the film thickness decreases across a ritical thickness of several monolayers (MLs), but its driving mechanism remains controversial. We have studied the thickness-dependent MIT of the ferromagnetic metal La${}_{0.6}$Sr${}_{0.4}$MnO${}_3$ by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. As the film thickness was decreased across the critical thickness of the MIT (6-8 ML), a gradual decrease of the ferromagnetic signals and a concomitant increase of paramagnetic signals were observed, while the Mn valence abruptly decreased towards Mn${}^{3+}$. These observations suggest that the ferromagnetic phase gradually and most likely inhomogeneously turns into the paramagnetic phase and both phases abruptly become insulating at the critical thickness.

12 pages, 3 figures

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• Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films
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Cited by in corpus (7)

• Strain-induced magnetization control in an oxide multiferroic heterostructure
• Anisotropic spin-density distribution and magnetic anisotropy of strained La${}_{1-x}$Sr${}_x$MnO${}_3$ thin films: Angle-dependent x-ray magnetic circular dichroism
• Electronic and magnetic properties of off-stoichiometric Co${}_2$Mn${}_{\beta }$Si/MgO interfaces studied by x-ray magnetic circular dichroism
• Relationship between charge redistribution and ferromagnetism at the heterointerface between perovskite oxides LaNiO${}_3$ and LaMnO${}_3$
• Alternation of Magnetic Anisotropy Accompanied by Metal-Insulator Transition in Strained Ultrathin Manganite Heterostructures
• Temperature evolution of magnetic phases near the thickness-dependent metal-insulator transition in La${}_{1-x}$Sr${}_x$MnO${}_3$ thin films observed by XMCD
• Anisotropic Charge Distribution Induced by Spin Polarization in La${}_{0.6}$Sr${}_{0.4}$MnO${}_3$ Thin Films Studied by X-ray Magnetic Linear Dichroism