Scaling behavior of ferroelectric FET with reduction in number of domains in ferroelectric layer

With the gate-length scaling, the number of domains in FeFET is reduced to a few or a single domain. In this paper, we investigate the effect of multi-domains versus few/single-domain behavior in FeFET. The abrupt polarization switching behavior of a single-domain is obtained by modifying the Preisach model in which the difference between saturation and remnant polarization (PsPr) is reduced. We show that for the same program/erase voltage, a two-times higher memory window can be achieved with single/few-domains FeFET than the multi-domain FeFET. Further, at fixed program/erase voltage, the scaling behavior shows improved variability due to increased polarization-induced vertical field with single-domain FeFET. We present an optimized device with a single-domain FeFET having a low operating voltage of ±2.4 V but with the same device performance that can be achieved for multi-domain FeFET having a higher operating voltage of ±5 V, which is highly promising for low power applications.

A Dynamic Compact Model for Ferroelectric Capacitance

A non-quasi-static model for ferroelectric capacitance is developed in this letter. A state transition in the voltage and time domains between two polarization states is formulated first. The quasi-static model is derived from the state transition of voltage domain, and supports the minor loops. Different from the Preisach model, an initial state is supported, and the modulated coercive voltages are responsible for minor loops. The non-quasi -static model is then derived with the state transition in the time domain, similar to a relaxation approximation in MOSFET modeling. The non-quasi-static model reproduces the saturation loop, minor loops, the frequency-dependent characteristics of measured ferroelectric capacitances, with their origins explained from polarization switching relaxation. The pulse width dependent switching is well reproduced with the model.

A Dynamic Compact Model for Ferroelectric Capacitance

A non-quasi-static model for ferroelectric capacitance is developed in this letter. A state transition in the voltage and time domains between two polarization states is formulated first. The quasi-static model is derived from the state transition of voltage domain, and supports the minor loops. Different from the Preisach model, an initial state is supported, and the modulated coercive voltages are responsible for minor loops. The non-quasi -static model is then derived with the state transition in the time domain, similar to a relaxation approximation in MOSFET modeling. The non-quasi-static model reproduces the saturation loop, minor loops, the frequency-dependent characteristics of measured ferroelectric capacitances, with their origins explained from polarization switching relaxation. The pulse width dependent switching is well reproduced with the model.

Research of Probability-Based Tunneling Magnetoresistive Sensor Static Hysteresis Model

Tunneling magnetoresistive (TMR) sensors have broad application prospects because of their high sensitivity and small volume. However, the inherent hysteresis characteristics of TMR affect its applications in high accuracy scenarios. It is essential to build a model to describe the attributes of hysteresis of TMR accurately. Preisach model is one of the popular models to describe the behavior of inherent hysteresis for TMR, whereas it presents low accuracy in high-order hysteresis reversal curves. Furthermore, the traditional Preisach model has strict congruence constraints, and the amount of data seriously affects the accuracy. This paper proposes a hysteresis model from a probability perspective. This model has the same computational complexity as the classic Preisach model while presenting higher accuracy, especially in high-order hysteresis reversal curves. When measuring a small amount of data, the error of this method is significantly reduced compared with the classical Preisach model. Besides, the proposed model’s congruence in this paper only needs equal vertical chords.

Novel Deperming Protocols to Reduce Demagnetizing Time and Improve the Performance for the Magnetic Silence of Warships

Magnetic silence of warships is necessary to prevent damage caused by the magnetic mines detecting the magnetic field of the warship. Anhysteretic and Deperm-ME protocols are used to reduce permanent magnetization among magnetic signals. However, they have some disadvantages. Therefore, this paper proposes an effective deperming protocol that is easily controlled and reduces the demagnetization time. A protocol composed of two Anhysteretic protocols is presented using the Preisach model to easily manage and ensure excellent performance. Each stage has its own advantages by considering the Preisach density distribution. In Stage 1, the existing magnetic history is erased, and the demagnetization time is reduced. In Stage 2, the demagnetization performance is improved. The effectiveness of the protocol was verified via simulations using the Preisach model and experiments using a specimen. When the proposed protocol was applied, the results were excellent when applying Anhysteretic and Deperm-ME. In addition, even if the number of magnetic fields was reduced by 4 and 8 in the proposed protocol, the demagnetization result was maintained. Therefore, if the proposed protocol is applied, excellent demagnetization results can be obtained and the time required to perform demagnetization can be reduced, thereby improving the operational capability of the warship.

Monitoring Spin-Crossover Properties by Diffused Reflectivity

In this work we present a detailed study showing the importance of the Kubelka-Munk (KM) correction in the analysis of diffuse reflectivity measurements to characterize spin crossover compounds. Combined reflectance and magnetic susceptibility measurements are carried out as a function of temperature or time to highlight the conditions under which this correction becomes critical. In particular, we investigate the influence of the color contrast between the two spin states on the reflectance measurements. Interestingly, the samples’ contrast seems to play an important role on the spin-like domain structure as suggested by the symmetry of the FORC diagrams. These latest results are discussed within the framework of Classical Preisach model (CPM).

Extraction of Preisach model parameters for fluorite-structure ferroelectrics and antiferroelectrics

Flourite-structure ferroelectrics (FEs) and antiferroelectrics (AFEs) such as HfO2 and its variants have gained copious attention from the semiconductor community, because they enable complementary metal-oxide-semiconductor (CMOS)-compatible platforms for high-density, high-performance non-volatile and volatile memory technologies. While many individual experiments have been conducted to characterize and understand fluorite-structure FEs and AFEs, there has been little effort to aggregate the information needed to benchmark and provide insights into their properties. We present a fast and robust modeling framework that automatically fits the Preisach model to the experimental polarization ($$Q_{FE}$$ Q FE ) versus electric field ($$E_{FE}$$ E FE ) hysteresis characterizations of fluorite-structure FEs. The modifications to the original Preisach model allow the double hysteresis loops in fluorite-structure antiferroelectrics to be captured as well. By fitting the measured data reported in the literature, we observe that ferroelectric polarization and dielectric constant decrease as the coercive field rises in general.

Preisach Elasto-Plastic Model for Mild Steel Hysteretic Behavior-Experimental and Theoretical Considerations

The Preisach model already successfully implemented for axial and bending cyclic loading is applied for modeling of the plateau problem for mild steel. It is shown that after the first cycle plateau disappears an extension of the existing Preisach model is needed. Heat dissipation and locked-in energy is calculated due to plastic deformation using the Preisach model. Theoretical results are verified by experiments performed on mild steel S275. The comparison of theoretical and experimental results is evident, showing the capability of the Presicah model in predicting behavior of structures under cyclic loading in the elastoplastic region. The purpose of this paper is to establish a theoretical background for embedded sensors like regenerated fiber Bragg gratings (RFBG) for measurement of strains and temperature in real structures. In addition, the present paper brings a theoretical base for application of nested split-ring resonator (NSRR) probes in measurements of plastic strain in real structures.