Local Magnetoelectric Effect in La-Doped BiFeO3 Multiferroic Thin Films Revealed by Magnetic-Field-Assisted Scanning Probe Microscopy

Pan, Danfeng; Zhou, Ming-Xiu; Lu, Zengxing; Zhang, Hao; Liu, Junming; Wang, Guanghou; Wan, Jing

doi:10.1186/s11671-016-1534-2

Cited by 12 publications

(4 citation statements)

References 31 publications

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“…Zavaliche et al were the first to demonstrate the direct imaging of electrically switched magnetic orientation of self-organized CoFe 2 O 4 columns in a BiFeO 3 thin-film matrix [17]. The results so far have mostly been only qualitative in nature, and an accurate quantitative estimation of order parameter changes at the nanoscale is still a challenge [18]. Some reports claim a rough estimation of the local ME coefficient using a change of MFM contrast [19,20].…”

Section: Introductionmentioning

confidence: 99%

Stress induced magnetic-domain evolution in magnetoelectric composites

et al. 2018

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Local observation of the stress mediated magnetoelectric (ME) effect in composites has gained a great deal of interest over the last decades. However, there is an apparent lack of rigorous methods for a quantitative characterization of the ME effect at the local scale, especially in polycrystalline microstructures. In the present work, we address this issue by locally probing the surface magnetic state of barium titante-hexagonal barium ferrite (BaTiO-BaFeO) ceramic composites using magnetic force microscopy (MFM). The effect of the piezoelectrically induced local stress on the magnetostrictive component (BaFeO, BaM) was observed in the form of the evolution of the magnetic domains. The local piezoelectric stress was induced by applying a voltage to the neighboring BaTiO grains, using a conductive atomic force microscopy tip. The resulting stochastic evolution of magnetic domains was studied in the context of the induced magnetoelastic anisotropy. In order to overcome the ambiguity in the domain changes observed by MFM, certain generalizations about the observed MFM contrast are put forward, followed by application of an algorithm for extracting the average micromagnetic changes. An average change in domain wall thickness of 50 nm was extracted, giving a lower limit on the corresponding induced magnetoelastic anisotropy energy. Furthermore, we demonstrate that this induced magnetomechanical energy is approximately equal to the K magnetocrystalline anisotropy constant of BaM, and compare it with a modeled value of applied elastic energy density. The comparison allowed us to judge the quality of the interfaces in the composite system, by roughly gauging the energy conversion ratio.

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Section: Introductionmentioning

confidence: 99%

Stress induced magnetic-domain evolution in magnetoelectric composites

et al. 2018

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“…One of the efficient means is to dope them at different sites of the perovskite lattice. Doping of BFO has been extensively studied in the past: there were reports on Tb [ 10 ], La [ 11 , 12 ], Ce [ 13 ], Eu, Gd, Dy [ 14 ] doping for A-site and Ti [ 8 ], Cr [ 15 ], Zr [ 16 ], Mn [ 17 ] substitutions at B-site. Using these substitutions it was possible to stabilize the valence of iron with the simultaneous decrease of conductivity.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Piezoelectric Properties and Phase Separation in Pure and La-Doped BiFeO3 Films Prepared by Sol–Gel Method

et al. 2021

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Pure BiFeO3 (BFO) and doped Bi0.9La0.1FeO3 (BLFO) thin films were prepared on Pt/TiO2/SiO2/Si substrates by a modified sol–gel technique using a separate hydrolysis procedure. The effects of final crystallization temperature and La doping on the phase structure, film morphology, and nanoscale piezoelectric properties were investigated. La doping and higher crystallization temperature lead to an increase in the grain size and preferred (102) texture of the films. Simultaneously, a decrease in the average effective piezoelectric coefficient (about 2 times in La-doped films) and an increase in the area of surface non-polar phase (up to 60%) are observed. Phase separation on the films’ surface is attributed to either a second phase or to a non-polar perovskite phase at the surface. As compared with undoped BFO, La-doping leads to an increase in the average grain size and self-polarization that is important for future piezoelectric applications. It is shown that piezoelectric activity is directly related to the films’ microstructructure, thus emphasizing the role of annealing conditions and La-doping that is frequently used to decrease the leakage current in BFO-based materials.

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“…[37][38][39][40] On the other hand, modeling predicts complex domain evolution in composites. [41][42][43] PFM based investigation (direct ME effect) is expected to reveal a strong modulation of the local piezoresponse (i.e., polarization) as a function of the externally applied magnetic field [20][21][22][23][24][25][26][27][28] giving an indirect insight into the spatial distribution of the local magnetoelectro-mechanical interactions.…”

Section: Introductionmentioning

confidence: 99%

“…A few examples of such phenomena include electrical conduction at ferroelectric/ferroelastic domain walls, [9][10][11][12] polarization dynamics in ferroelectrics, [13][14][15][16][17][18] temperature/time/ voltage dependent study of ergodicity (time dependence) of polarization in relaxor-ferroelectrics, 14,19 and local magnetoelectricity. [20][21][22][23][24][25][26][27][28] Probing such local phenomena essentially requires measuring a response I ij (x i , P j ) on an X × Y grid, as a function of a spectral parameter P j (j = 1,…,M); where x i is the spatial coordinate index (i = 1,…,N; N = X × Y). The format of such spectroscopic acquisition could be selected in two different ways: (i) a point-by-point acquisition of the response as a function of P j , or (ii) a sequence of scans at different values of P j .…”

Section: Introductionmentioning

confidence: 99%

Sequential piezoresponse force microscopy and the ‘small-data’ problem

et al. 2018

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The term big-data in the context of materials science not only stands for the volume, but also for the heterogeneous nature of the characterization data-sets. This is a common problem in combinatorial searches in materials science, as well as chemistry. However, these data-sets may well be 'small' in terms of limited step-size of the measurement variables. Due to this limitation, application of higher-order statistics is not effective, and the choice of a suitable unsupervised learning method is restricted to those utilizing lower-order statistics. As an interesting case study, we present here variable magnetic-field Piezoresponse Force Microscopy (PFM) study of composite multiferroics, where due to experimental limitations the magnetic field dependence of piezoresponse is registered with a coarse step-size. An efficient extraction of this dependence, which corresponds to the local magnetoelectric effect, forms the central problem of this work. We evaluate the performance of Principal Component Analysis (PCA) as a simple unsupervised learning technique, by pre-labeling possible patterns in the data using Density Based Clustering (DBSCAN). Based on this combinational analysis, we highlight how PCA using non-central second-moment can be useful in such cases for extracting information about the local material response and the corresponding spatial distribution.

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Local Magnetoelectric Effect in La-Doped BiFeO3 Multiferroic Thin Films Revealed by Magnetic-Field-Assisted Scanning Probe Microscopy

Cited by 12 publications

References 31 publications

Stress induced magnetic-domain evolution in magnetoelectric composites

Stress induced magnetic-domain evolution in magnetoelectric composites

Nanoscale Piezoelectric Properties and Phase Separation in Pure and La-Doped BiFeO3 Films Prepared by Sol–Gel Method

Sequential piezoresponse force microscopy and the ‘small-data’ problem

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