Strain-Induced Ferromagnetism in Antiferromagnetic LuMnO3 Thin Films

Diagram of the processes in the LuMnO3 layers studied. The layer is highly strained close to the substrate, which leads to a ferromagnetic (FM) order there. As the distance grows, the strain decreases so that two antiferromagnetic (AFM) orders appear: the spin spirals and the E-type, where two spins point in one direction and the next two in the other.
Diagram of the processes in the LuMnO3 layers studied. The layer is highly strained close to the substrate, which leads to a ferromagnetic (FM) order there. As the distance grows, the strain decreases so that two antiferromagnetic (AFM) orders appear: the spin spirals and the E-type, where two spins point in one direction and the next two in the other.

Abstract:

Single phase and strained LuMnO3 thin films are discovered to display coexisting ferromagnetic and antiferromagnetic orders. A large moment ferromagnetism (≈1μB), which is absent in bulk samples, is shown to display a magnetic moment distribution that is peaked at the highly strained substrate-film interface. We further show that the strain-induced ferromagnetism and the antiferromagnetic order are coupled via an exchange field, therefore demonstrating strained rare-earth manganite thin films as promising candidate systems for new multifunctional devices.
Keywords: Multiferroic thin films; Orthorhombic rare-earth manganites; Neutron reflectometry; Antiferromagnetism; Ferromagnetism; Strain;

Facility: ENE, LNS, LDM, U Fribourg, ETHZ, ILL, LMX, Thin Films and Interfaces

Reference: J. S. White, M. Bator, Y. Hu, H. Luetkens, J. Stahn, S. Capelli, S. Das, M. Döbeli, Th. Lippert, V. K. Malik, J. Martynczuk, A. Wokaun, M. Kenzelmann, Ch. Niedermayer, and C.W. Schneider, Phys. Rev. Lett. 111, 037201 (2013)

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