The negative dielectric permittivity of polycrystalline barium titanate nanofilms under high-strength kHz-AC fields

Zhang, Ming-Ran; Su, Yu

doi:10.1016/j.ijsolstr.2022.111939

Cited by 4 publications

(4 citation statements)

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“…Another factor that can affect the switching speed both directly and through the electric field is the grain size. Indeed, using phase-field modeling, it has been shown that the grain pattern (e.g., grain size and orientation) and the existence of grain boundaries affect the polarization switching or domain evolution dynamics in ferroelectric perovskite films [19,20]. However, the HZO grain size distributions acquired from the AFM and SEM images indicate that these distributions are very similar for both samples (Figure 6c-f).…”

Section: Resultsmentioning

confidence: 97%

“…In addition to HfO 2 -specific factors, the polycrystallinity of the material and the fundamental properties of ferroelectrics influence the switching speed. For other ferroelectric polycrystalline films, it has been shown that the grain pattern (e.g., grain size and orientation) and grain boundaries affect the polarization switching or domain evolution dynamics in ferroelectric nanofilms [19,20]. Furthermore, the depolarization field of spontaneous polarization, an intrinsic feature of ferroelectrics, has been reported to be the cause of the slowing down of polarization switching [21,22].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Chouprik,

Savelyeva,

Korostylev

et al. 2023

Nanomaterials

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The nanosecond speed of information writing and reading is recognized as one of the main advantages of next-generation non-volatile ferroelectric memory based on hafnium oxide thin films. However, the kinetics of polarization switching in this material have a complex nature, and despite the high speed of internal switching, the real speed can deteriorate significantly due to various external reasons. In this work, we reveal that the domain structure and the dielectric layer formed at the electrode interface contribute significantly to the polarization switching speed of 10 nm thick Hf0.5Zr0.5O2 (HZO) film. The mechanism of speed degradation is related to the generation of charged defects in the film which accompany the formation of the interfacial dielectric layer during oxidization of the electrode. Such defects are pinning centers that prevent domain propagation upon polarization switching. To clarify this issue, we fabricate two types of similar W/HZO/TiN capacitor structures, differing only in the thickness of the electrode interlayer, and compare their ferroelectric (including local ferroelectric), dielectric, structural (including microstructural), chemical, and morphological properties, which are comprehensively investigated using several advanced techniques, in particular, hard X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and electron beam induced current technique.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Chouprik,

Savelyeva,

Korostylev

et al. 2023

Nanomaterials

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“…This could be because of the inertia of molecules and ions. [ 72,73 ] That's why the dielectric constant values of the prepared ceramics were constant at high frequencies.…”

Section: Resultsmentioning

confidence: 99%

Effect of Cobalt Doping on Structural, Morphological, Magnetic, Electrical, and Optical Properties of (Ba_0.7Sr_0.3)_0.98Ca_0.02Ti_1−XCo_xO₃ Ceramics for Device Applications

Mahmud

Ahamed

Khan

2023

Physica Status Solidi (a)

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Considering the multifunctional performance, the (Ba0.7Sr0.3)0.98Ca0.02Ti1−xCoxO3 (x = 0.00–0.2) ceramics are successfully synthesized using the traditional solid‐phase reaction method. The effect of cobalt doping on the samples’ structural, morphological, magnetic, electrical, and optical characteristics is elucidated. Raman spectroscopy and X‐ray diffraction data confirm the dopants’ integration into the cubic perovskite microstructure. At room temperature, the magnetization–magnetic field intensity hysteresis loops from vibrating sample magnetometer reveal the samples’ ferromagnetic character, with a maximum magnetization of 0.091 emu g−1 achieved for x = 15%. The real part of the initial permeability demonstrates that the replacement of Co2+ causes a shift in resonance toward higher frequencies above 85 MHz, indicating the potential of the synthesized ceramics for high‐frequency magnetic applications. The variation in dielectric characteristics from 100 Hz to 10 MHz is explained using electron hopping on octahedral sites and Maxwell–Wagner's model. The increase of AC conductivity in the high‐frequency region is consistent with the strengthening of the grain effect on the conduction mechanism, which supports the small‐range polaron‐hopping theory. The complex electric modulus's peak (M′′) shifts toward a higher‐frequency region with cobalt content, suggesting a reduction in the relaxation rate. The optical bandgap is observed to decrease from 3.08 to 2.96 eV with cobalt content.

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“…For ferroelectric HfO 2 , by means of the IFM model, it has been demonstrated that polarization switching accelerates and field distribution shrinks during the training process of the as-prepared film (the so-called wake-up effect) [ 11 ]. An alternative way to consider the impact of the polycrystalline microstructure is based on phase-field modelling, which showed that the grain pattern (e.g., grain size and orientation) and the existence of grain boundaries affect the polarization switching or domain evolution dynamics in ferroelectric nanofilms [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Polarization Switching Kinetics in Thin Ferroelectric HZO Films

Kondratyuk

Chouprik

2022

Nanomaterials

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Ferroelectric polycrystalline HfO2 thin films are the most promising material for the implementation of novel non-volatile ferroelectric memories because of their attractive properties, such as compatibility with modern Si technology, perfect scalability, low power consumption and high endurance. However, for the commercialization of ferroelectric memory, some crucial aspects of its operation should be addressed, including the polarization switching mechanism that determines the switching speed. Although several reports on polarization switching kinetics in HfO2-based layers already exist, the physical origin of retardation behavior of polarization switching at the low and medium switching fields remains unclear. In this work, we examine several models of switching kinetics that can potentially explain or describe retardation behavior observed in experimental switching kinetics for Hf0.5Zr0.5O2 (HZO)-based capacitors and propose a new model. The proposed model is based on a statistical model of switching kinetics, which has been significantly extended to take into account the specific properties of HZO. The model includes contributions of the depolarization field and the built-in internal field originating from the charge injection into the functional HZO layer during the read procedure as well as in-plane inhomogeneity of the total electric field in ferroelectric. The general model of switching kinetics shows excellent agreement with the experimental results.

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The negative dielectric permittivity of polycrystalline barium titanate nanofilms under high-strength kHz-AC fields

Cited by 4 publications

References 63 publications

Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Effect of Cobalt Doping on Structural, Morphological, Magnetic, Electrical, and Optical Properties of (Ba_0.7Sr_0.3)_0.98Ca_0.02Ti_1−XCo_xO₃ Ceramics for Device Applications

Polarization Switching Kinetics in Thin Ferroelectric HZO Films

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The negative dielectric permittivity of polycrystalline barium titanate nanofilms under high-strength kHz-AC fields

Cited by 4 publications

References 63 publications

Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Effect of Domain Structure and Dielectric Interlayer on Switching Speed of Ferroelectric Hf0.5Zr0.5O2 Film

Effect of Cobalt Doping on Structural, Morphological, Magnetic, Electrical, and Optical Properties of (Ba0.7Sr0.3)0.98Ca0.02Ti1−XCoxO3 Ceramics for Device Applications

Polarization Switching Kinetics in Thin Ferroelectric HZO Films

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Effect of Cobalt Doping on Structural, Morphological, Magnetic, Electrical, and Optical Properties of (Ba_0.7Sr_0.3)_0.98Ca_0.02Ti_1−XCo_xO₃ Ceramics for Device Applications