Thickness dependence of La0.7Sr0.3MnO3/PbZr0.2Ti0.8O3 magnetoelectric interfaces

Abstract

Magnetoelectric materials have great potential to revolutionize electronic devices due to the coupling of their electric and magnetic properties. Thickness varying La 0.7 Sr 0.3 MnO 3 (LSMO)/ PbZr 0.2 Ti 0.8 O 3 (PZT) heterostructures were built and measured in this article by valence sensitive x-ray absorption spectroscopy. The sizing effects of the heterostructures on the LSMO/PZT magnetoelectric interfaces were investigated through the behavior of Mn valence, a property associated with the LSMO magnetization. We found that Mn valence increases with both LSMO and PZT thickness. Piezoresponse force microscopy revealed a transition from monodomain to polydomain structure along the PZT thickness gradient. The ferroelectric surface charge may change with domain structure and its effects on Mn valence were simulated using a two-orbital double-exchange model. The screening of ferroelectric surface charge increases the electron charges in the interface region, and greatly changes the interfacial Mn valence, which likely plays a leading role in the interfacial magnetoelectric coupling. The LSMO thickness dependence was examined through the combination of two detection modes with drastically different attenuation depths. The different length scales of these techniques' sensitivity to the atomic valence were used to estimate the depth dependence Mn valence. A smaller interfacial Mn valence than the bulk was found by globally fitting the experimental results. V C 2015 AIP Publishing LLC.

Electrostatic potential and valence modulation in La0.7Sr0.3MnO3 thin films

“…Growth parameters are discussed in the Methods section 16 . Multiple thicknesses were measured within the range of 1–16 u.c.…”

“…To better understand the observed thickness-dependent change in valence, we fit both FY and TEY data using a layer-dependent valence model developed in a previous work 16 . The fit to the experimental data is shown in Fig.…”

“…This experimental approach has been previously used to study the layer-by-layer valence change in LSMO/PbZr 0.2 Ti 0.8 O 3 (PZT) magnetoelectric heterostructures 16 . The surface charge of the ferroelectric PZT layer was found to be screened by the carriers in the LSMO layer, causing a change in the interfacial Mn valence depending on the ferroelectric polarization direction.…”

Thickness‐induced anomalous angular‐dependent magnetoresistance of La2/3Sr1/3MnO3 thin films grown on SrTiO3

“…Thin films of the doped perovskite manganites, La 1− x Sr x MnO 3 , have attracted considerable great attention due to their fascinating physical properties . The transport properties of La 1− x Sr x MnO 3 films are sensitive to the film thickness and the lattice strain.…”

Ab initiostudy of magnetoelectric coupling in La0.66Sr0.33MnO3 / PbZr0.2Ti0.8O3multiferroic heterostructures

“…The authors concluded that a large magnetoelectric response in LSMO/PZT films was most likely produced by a modified interfacial spin configuration [7]. Zhou et al measured the effective valency of Mn atoms in LSMO/PZT heterostructures using valence sensitive x-ray absorption spectroscopy [19]. The measurements showed that the Mn valency increased with increasing thickness of the LSMO and PZT films.…”