In perovskite complex oxides, the strain has been established as a promising approach for tuning the oxygen evolution reaction (OER) performance by the manipulated electronic structure and interaction/coupling. In this study, we have employed rigid epitaxial, flexible freestanding, and van der Waals La2/3Sr1/3MnO3 (LSMO) to investigate the strain effects on OER, which are different in stress strength and range via lattice mismatch and curvature change. It was found that the OER performances as a function of strain exhibited volcano and monotonous trends in rigid and flexible LSMO, respectively. The findings suggest that distinguished oxygen activation energy in varied lattice fields also plays a crucial role in the epitaxial LSMO in contrast to the pure strain effect in the flexible LSMO. Our results not only fundamentally clarify the effort of strain but also technologically provide an effective route to engineer the electronic structure for modified OER performance by perovskite complex oxides.

Motivated by the fast-developing spin dynamics in ferromagnetic/piezoelectric structures, this study attempts to manipulate magnons (spin-wave excitations) by the converse magnetoelectric (ME) coupling. Herein, electric field (E-field) tuning magnetism, especially the surface spin wave, is accomplished in Ni/0.7Pb(Mg1/3}Nb2/3})O3—0.3PbTiO3 (PMN—PT) multiferroic heterostructures. The Kerr signal (directly proportional to magnetization) changes of Ni film are observed when direct current (DC) or alternative current (AC) voltage is applied to PMN—PT substrate, where the signal can be modulated breezily even without extra magnetic field (H-field) in AC-mode measurement. Deserved to be mentioned, a surface spin wave switch of “1” (i.e., “on”) and “0” (i.e., “off”) has been created at room temperature upon applying an E-field. In addition, the magnetic anisotropy of heterostructures has been investigated by E-field-induced ferromagnetic resonance (FMR) shift, and a large 490 Oe shift of FMR is determined at the angle of 45° between H-field and heterostructure plane.

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The magnetic field response of an electrochemistry process, such as the oxygen evolution reaction (OER), provides not only a strategy for enhanced catalytic activity by applying an external field but also a platform for revealing the functionality of the multiple degrees of freedom of the catalyst. However, the mechanism of the magnetic field tuneable OER is controversial. The strong correlation between the d and p orbitals of transition metal and oxygen still puzzles the dominant role of spin in an OER process. Here in this study, we have employed the manganite La 0.7 Sr 0.2 Ca 0.1 MnO 3 as the ferromagnetic OER catalyst, which has a ferromagnetic/paramagnetic transition (T C ) around the room temperature. It is found that the overpotential can be reduced by ∼18% after applying a 5 kOe magnetic field. Furthermore, this magnetic field can trigger a further improvement of the OER performance, and it demonstrates a strong temperature dependence which is incongruent with its magnetoresistive behavior. So our experiments suggest that the observed magnetic response originates dominantly from the triplet state of the O 2 , where the spin-polarized d and oxygen p orbitals lower the Gibbs free energy for every reaction step in OER. This study offers experimental evidence on comprehending the spin degree in the OER process, meanwhile benefiting the further design and engineering of the promising magnetic electrochemistry catalysts.

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