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Jia QQ, Teri G, Luo JQ, Ni HF, Huang PZ, Lun MM, Zhang ZX, Zhang Y, Fu DW. Experimental Observation of the Fully Ferroelectric-Fully Ferroelastic Effect in Multiferroic Hybrid Perovskites. J Am Chem Soc 2024. [PMID: 39034829 DOI: 10.1021/jacs.4c06929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Since the concept of "multiferroic" was first proposed in 1968, the coupling effect between different ferroic orders has attracted great interest in energy, information, and biomedical fields. However, the fully ferroelectric-fully ferroelastic effect has never been experimentally observed in hybrid perovskites, even though this effect was predicted to exist half a century ago. Realizing such cross-linking effects of polarization vectors and strain tensors has always been a huge challenge because of the complex difference in these two ferroic origins. Here, we report a multiferroic with full ferroelectricity and full ferroelasticity in two-dimensional (2D) hybrid perovskites based on ferroelectrochemistry. The dynamic molecular reorientations endow (cyclohexanemethylaminium)2PbCl4 with a desired symmetry change of 4̅2mFmm2 at a Curie temperature of 411.8 K. More strikingly, the switchable evolution of ferroelastic domains was directly observed under the control of either electric or mechanical fields, which is the first experimental observation of a fully ferroelectric-fully ferroelastic effect in hybrid perovskites. This work would provide new insights into understanding the intrinsic cross-linking mechanism between ferroelectricity and ferroelasticity toward the development of multichannel interactive microelectronic devices.
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Affiliation(s)
- Qiang-Qiang Jia
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Gele Teri
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Jia-Qi Luo
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Hao-Fei Ni
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Pei-Zhi Huang
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Meng-Meng Lun
- Ordered Matter Science Research Center, Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
| | - Zhi-Xu Zhang
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Yi Zhang
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
| | - Da-Wei Fu
- Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua 321004, P. R. China
- Ordered Matter Science Research Center, Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China
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2
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Scott JJR, Lu G, Rodriguez BJ, MacLaren I, Salje EKH, Arredondo M. Evidence of the Monopolar-Dipolar Crossover Regime: A Multiscale Study of Ferroelastic Domains by In Situ Microscopy Techniques. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400646. [PMID: 38686673 DOI: 10.1002/smll.202400646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/03/2024] [Indexed: 05/02/2024]
Abstract
The elastic interaction between kinks (and antikinks) within domain walls plays a pivotal role in shaping the domain structure, and their dynamics. In bulk materials, kinks interact as elastic monopoles, dependent on the distance between walls (d-1) and typically characterized by a rigid and straight domain configuration. In this work the evolution of the domain structure is investigated, as the sample size decreases, by the means of in situ heating microscopy techniques on free-standing samples. As the sample size decreases, a significant transformation is observed: domain walls exhibit pronounced curvature, accompanied by an increase in both domain wall and junction density. This transformation is attributed to the pronounced influence of kinks, inducing sample warping, where "dipole-dipole" interactions are dominant (d-2). Moreover, a critical thickness range that delineates a crossover between the monopolar and dipolar regimens is experimentally identified and corroborated by atomic simulations. These findings are relevant for in situ TEM studies and for the development of novel devices based on free-standing ferroic thin films and nanomaterials.
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Affiliation(s)
- John J R Scott
- School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland
| | - Guangming Lu
- School of Environmental and Material Engineering, Yantai University, Yantai, 264005, China
| | - Brian J Rodriguez
- School of Physics, University College Dublin, Dublin, D04 V1W8, Ireland
| | - Ian MacLaren
- School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Ekhard K H Salje
- Department of Earth Sciences, University of Cambridge, Cambridge, G12 8QQ, UK
| | - Miryam Arredondo
- School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland
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3
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Eckstein JT, Wiseman OJ, Carpenter MA, Salje EKH. Acoustic emission of kidney stones: a medical adaptation of statistical breakdown mechanisms. Urolithiasis 2024; 52:36. [PMID: 38376662 PMCID: PMC10879257 DOI: 10.1007/s00240-024-01531-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/09/2024] [Indexed: 02/21/2024]
Abstract
Kidney stones have a prevalence rate of > 10% in some countries. There has been a significant increase in surgery to treat kidney stones over the last 10 years, and it is crucial that such techniques are as effective as possible, while limiting complications. A selection of kidney stones with different chemical and structural properties were subjected to compression. Under compression, they emit acoustic signals called crackling noise. The variability of the crackling noise was surprisingly great comparing weddellite, cystine and uric acid stones. Two types of signals were found in all stones. At high energies of the emitted sound waves, we found avalanche behaviour, while all stones also showed signals of local, uncorrelated collapse. These two types of events are called 'wild' for avalanches and 'mild' for uncorrelated events. The key observation is that the crossover from mild to wild collapse events differs greatly between different stones. Weddellite showed brittle collapse, extremely low crossover energies (< 5 aJ) and wild avalanches over 6 orders of magnitude. In cystine and uric acid stones, the collapse was more complicated with a dominance of local "mild" breakings, although they all contained some stress-induced collective avalanches. Cystine stones had high crossover energies, typically [Formula: see text] 750 aJ, and a narrow window over which they showed wild avalanches. Uric acid stones gave moderate values of crossover energies, [Formula: see text] 200 aJ, and wild avalanche behaviour for [Formula: see text] 3 orders of magnitude. Further research extended to all stone types, and measurement of stone responses to different lithotripsy strategies, will assist in optimisation of settings of the laser and other lithotripsy devices to insight fragmentation by targeting the 'wild' avalanche regime.
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Affiliation(s)
- Jack T Eckstein
- Department of Earth Sciences, University of Cambridge, Downing St., Cambridge, Cambridgeshire, CB2 3EQ, UK.
| | - Oliver J Wiseman
- Department of Urology, Cambridge University Hospitals NHS Foundation Trust, Hill's Rd., Cambridge, Cambridgeshire, CB2 0QQ, UK
| | - Michael A Carpenter
- Department of Earth Sciences, University of Cambridge, Downing St., Cambridge, Cambridgeshire, CB2 3EQ, UK
| | - Ekhard K H Salje
- Department of Earth Sciences, University of Cambridge, Downing St., Cambridge, Cambridgeshire, CB2 3EQ, UK
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4
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Qiu S, Fu H. Extended planar defects of oxygen vacancies in ferroelectric [Formula: see text] and impact on ferroelectricity. Sci Rep 2023; 13:19578. [PMID: 37949911 PMCID: PMC10638332 DOI: 10.1038/s41598-023-46489-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023] Open
Abstract
Extended defects of vacancies in ferroelectrics (FE), where vacancies spread over an extended space, are of critical importance in terms of understanding the long-standing problems such as polarization fatigue and aging. However, extended defects in FEs are poorly understood. Here we investigate the extended planar oxygen vacancies in ferroelectric [Formula: see text] using density functional theory and the modern theory of polarization. Oxygen vacancies of different charge states, namely [Formula: see text], [Formula: see text], and [Formula: see text], are studied. We obtain interesting results such as: (i) The formation energy of planar [Formula: see text] vacancies can be very small (merely 0.54 eV) even under the oxygen-rich condition, which is considerably smaller than the formation energy (4.0 eV) of planar [Formula: see text] vacancies; (ii) Planar [Formula: see text] vacancies drastically reduce the ferroelectric polarization in [Formula: see text] by more than one order of magnitude, which provides a pivotal (theoretical) evidence that the planar oxygen vacancies could be the origin of polarization fatigue and imprinting. The polarization dead layer caused by planar oxygen vacancies is shown to be around 72 Å. Microscopic origin and insight, based on the local Ti-O relative displacements, are provided to understand these interesting phenomena.
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Affiliation(s)
- Shaohui Qiu
- Department of Physics, University of Arkansas, Fayetteville, AR 72701 USA
- Department of Chemistry and Physics, Southern Utah University, Cedar City, UT 84720 USA
| | - Huaxiang Fu
- Department of Physics, University of Arkansas, Fayetteville, AR 72701 USA
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5
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Rao A, Sanjay S, Dey V, Ahmadi M, Yadav P, Venugopalrao A, Bhat N, Kooi B, Raghavan S, Nukala P. Realizing avalanche criticality in neuromorphic networks on a 2D hBN platform. MATERIALS HORIZONS 2023; 10:5235-5245. [PMID: 37740285 DOI: 10.1039/d3mh01000g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Networks and systems which exhibit brain-like behavior can analyze information from intrinsically noisy and unstructured data with very low power consumption. Such characteristics arise due to the critical nature and complex interconnectivity of the brain and its neuronal network. We demonstrate a system comprising of multilayer hexagonal boron nitride (hBN) films contacted with silver (Ag), which can uniquely host two different self-assembled networks, which are self-organized at criticality (SOC). This system shows bipolar resistive switching between the high resistance state (HRS) and the low resistance state (LRS). In the HRS, Ag clusters (nodes) intercalate in the van der Waals gaps of hBN forming a network of tunnel junctions, whereas the LRS contains a network of Ag filaments. The temporal avalanche dynamics in both these states exhibit power-law scaling, long-range temporal correlation, and SOC. These networks can be tuned from one to another with voltage as a control parameter. For the first time, two different neural networks are realized in a single CMOS compatible, 2D material platform.
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Affiliation(s)
- Ankit Rao
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Sooraj Sanjay
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Vivek Dey
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Majid Ahmadi
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | - Pramod Yadav
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Anirudh Venugopalrao
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Navakanta Bhat
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Bart Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
- CogniGron Center, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Srinivasan Raghavan
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
| | - Pavan Nukala
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India.
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6
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Bronstein E, Zimmerman J, Rabkin E, Faran E, Talmon R, Shilo D. Enhancing the detection capabilities of nano-avalanches via data-driven classification of acoustic emission signals. Phys Rev E 2023; 108:045001. [PMID: 37978707 DOI: 10.1103/physreve.108.045001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 09/05/2023] [Indexed: 11/19/2023]
Abstract
Acoustic emission (AE) is a powerful experimental method for studying discrete and impulsive events termed avalanches that occur in a wide variety of materials and physical phenomena. A particular challenge is the detection of small-scale avalanches, whose associated acoustic signals are at the noise level of the experimental setup. The conventional detection approach is based on setting a threshold significantly larger than this level, ignoring "false" events with low AE amplitudes that originate from noise. At the same time, this approach overlooks small-scale events that might be true and impedes the investigation of avalanches occurring at the nanoscale, constituting the natural response of many nanoparticles and nanostructured materials. In this work, we develop a data-driven method that allows the detection of small-scale AE events, which is based on two propositions. The first includes a modification of the experimental conditions by setting a lower threshold compared to the conventional threshold, such that an abundance of small-scale events with low amplitudes are considered. Second, instead of analyzing several conventional scalar features (e.g., amplitude, duration, energy), we consider the entire waveform of each AE event and obtain an informative representation using dynamic mode decomposition. We apply the developed method to AE signals measured during the compression of platinum nanoparticles and demonstrate a significant enhancement of the detection range toward small-scale events that are below the conventional threshold.
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Affiliation(s)
- Emil Bronstein
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - Jonathan Zimmerman
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - Eugen Rabkin
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - Eilon Faran
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - Ronen Talmon
- Viterbi Faculty of Electrical and Computer Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
| | - Doron Shilo
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel
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7
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Nguyen CPT, Schoenherr P, Salje EKH, Seidel J. Crackling noise microscopy. Nat Commun 2023; 14:4963. [PMID: 37587105 PMCID: PMC10432464 DOI: 10.1038/s41467-023-40665-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 08/02/2023] [Indexed: 08/18/2023] Open
Abstract
Crackling noise is a scale-invariant phenomenon found in various driven nonlinear dynamical material systems as a response to external stimuli such as force or external fields. Jerky material movements in the form of avalanches can span many orders of magnitude in size and follow universal scaling rules described by power laws. The concept was originally studied as Barkhausen noise in magnetic materials and now is used in diverse fields from earthquake research and building materials monitoring to fundamental research involving phase transitions and neural networks. Here, we demonstrate a method for nanoscale crackling noise measurements based on AFM nanoindentation, where the AFM probe can be used to study the crackling of individual nanoscale features, a technique we call crackling noise microscopy. The method is successfully applied to investigate the crackling of individual topological defects, i.e. ferroelectric domain walls. We show that critical exponents for avalanches are altered at these nanoscale features, leading to a suppression of mixed-criticality, which is otherwise present in domains. The presented concept opens the possibility of investigating the crackling of individual nanoscale features in a wide range of material systems.
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Affiliation(s)
- Cam-Phu Thi Nguyen
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Peggy Schoenherr
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW, 2052, Australia
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Ekhard K H Salje
- Department of Earth Sciences, Cambridge University, Cambridge, UK.
| | - Jan Seidel
- School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW, 2052, Australia.
- ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), UNSW Sydney, Sydney, NSW, 2052, Australia.
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8
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Ma Z, Chen W, Cao X, Diao S, Liu Z, Ge J, Pan S. Criticality and Neuromorphic Sensing in a Single Memristor. NANO LETTERS 2023. [PMID: 37326403 DOI: 10.1021/acs.nanolett.3c00389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Resistive random access memory (RRAM) is an important technology for both data storage and neuromorphic computation, where the dynamics of nanoscale conductive filaments lies at the core of the technology. Here, we analyze the current noise of various silicon-based memristors that involves the creation of a percolation path at the intermediate phase of filament growth. Remarkably, we find that these atomic switching events follow scale-free avalanche dynamics with exponents satisfying the criteria for criticality. We further prove that the switching dynamics are universal and show little dependence on device sizes or material features. Utilizing criticality in memristors, we simulate the functionality of hair cells in auditory sensory systems by observing the frequency selectivity of input stimuli with tunable characteristic frequency. We further demonstrate a single-memristor-based sensing primitive for representation of input stimuli that exceeds the theoretical limits dictated by the Nyquist-Shannon theorem.
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Affiliation(s)
- Zelin Ma
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
| | - Wanjun Chen
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
| | - Xucheng Cao
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
| | - Shanqing Diao
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
| | - Zhiyu Liu
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
| | - Jun Ge
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
- Key Lab of Si-based Information Materials & Devices and Integrated Circuits Design, Department of Education of Guangdong Province, Guangzhou 510006, China
| | - Shusheng Pan
- Research Center for Advanced Information Materials (CAIM), Huangpu Research & Graduate School of Guangzhou University, Guangzhou 510555, China
- Solid State Physics & Material Research Laboratory, School of Physics and Material Science, Guangzhou University, Guangzhou 510006, China
- Key Lab of Si-based Information Materials & Devices and Integrated Circuits Design, Department of Education of Guangdong Province, Guangzhou 510006, China
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9
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Salje EKH, Kustov S. Dynamic domain boundaries: chemical dopants carried by moving twin walls. Phys Chem Chem Phys 2023; 25:1588-1601. [PMID: 36602278 DOI: 10.1039/d2cp04908b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Domain walls and specifically ferroelastic twin boundaries are depositaries and fast diffusion pathways for chemical dopants and intrinsic lattice defects. Ferroelastic domain patterns act as templates for chemical structures where the walls are the device and not the bulk. Several examples of such engineered domain boundaries are given. Moving twin boundaries are shown to carry with them the dopants, although the activation of this mechanism depends sensitively on the applied external force. If the force is too weak, the walls remain pinned while too strong forces break the walls free of the dopants and move them independently. Several experimental methods and approaches are discussed.
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Affiliation(s)
- E K H Salje
- Department of Earth Sciences, University of Cambridge, Cambridge, UK.
| | - S Kustov
- Department of Physics, University of Balearic Islands, 07122 Palma de Mallorca, Spain
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10
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Scott JJR, Casals B, Luo KF, Haq A, Mariotti D, Salje EKH, Arredondo M. Avalanche criticality in LaAlO[Formula: see text] and the effect of aspect ratio. Sci Rep 2022; 12:14818. [PMID: 36050337 PMCID: PMC9437108 DOI: 10.1038/s41598-022-18390-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
Ferroic domain dynamics, as a function of external stimuli, can be collectively described as scale-invariant avalanches characterised by a critical exponent that are sensitive to the complexity of the domain microstructure. The understanding and manipulation of these avalanches lies at the heart of developing novel applications such as neuromorphic computing. Here we combine in situ heating optical observations and mean-field analysis to investigate the collective domain behaviour in pure-ferroelastic lanthanum aluminate (LaAlO[Formula: see text]) as a function of aspect ratio, the ratio of sample length to width, where the movement of the domains is predominantly driven by thermal stresses via thermal expansion/contraction during heat cycling. Our observations demonstrate that the aspect ratio induces (1) distinctive domain microstructures at room temperature, (2) a deviation of dynamical behaviour at high temperatures and (3) critical exponent mixing in the higher aspect ratio samples that accompanies this behaviour. While the critical exponents of each aspect ratio fall within mean-field predicted values, we highlight the effect that the aspect ratio has in inducing exponent mixing. Hence, furthering our understanding towards tuning and controlling avalanches which is crucial for fundamental and applied research.
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Affiliation(s)
- John J. R. Scott
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
| | - Blai Casals
- Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ England, UK
| | - King-Fa Luo
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
| | - Atta Haq
- School of Engineering, Ulster University, Jordanstown, BT37 0QB Northern Ireland, UK
| | - Davide Mariotti
- School of Engineering, Ulster University, Jordanstown, BT37 0QB Northern Ireland, UK
| | - Ekhard K. H. Salje
- Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ England, UK
| | - Miryam Arredondo
- School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN Northern Ireland, UK
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11
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Casals B, Salje EKH. Energy exponents of avalanches and Hausdorff dimensions of collapse patterns. Phys Rev E 2021; 104:054138. [PMID: 34942752 DOI: 10.1103/physreve.104.054138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 11/05/2021] [Indexed: 11/07/2022]
Abstract
A simple numerical model to simulate athermal avalanches is presented. The model is inspired by the "porous collapse" process where the compression of porous materials generates collapse cascades, leading to power law distributed avalanches. The energy (E), amplitude (A_{max}), and size (S) exponents are derived by computer simulation in two approximations. Time-dependent "jerk" spectra are calculated in a single avalanche model where each avalanche is simulated separately from other avalanches. The average avalanche profile is parabolic, the scaling between energy and amplitude follows E∼A_{max}^{2}, and the energy exponent is ε = 1.33. Adding a general noise term in a continuous event model generates infinite avalanche sequences which allow the evaluation of waiting time distributions and pattern formation. We find the validity of the Omori law and the same exponents as in the single avalanche model. We then add spatial correlations by stipulating the ratio G/N between growth processes G (linked to a previous event location) and nucleation processes N (with new, randomly chosen nucleation sites). We found, in good approximation, a power law correlation between the energy exponent ε and the Hausdorff dimension H_{D} of the resulting collapse pattern H_{D}-1∼ɛ^{-3}. The evolving patterns depend strongly on G/N with the distribution of collapse sites equally power law distributed. Its exponent ɛ_{topo} would be linked to the dynamical exponent ε if each collapse carried an energy equivalent to the size of the collapse. A complex correlation between ɛ,ɛ_{topo}, and H_{D} emerges, depending strongly on the relative occupancy of the collapse sites in the simulation box.
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Affiliation(s)
- Blai Casals
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB23EQ, United Kingdom
| | - Ekhard K H Salje
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB23EQ, United Kingdom
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12
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Wang YN, Wang DM, Xin HH, Zhu YF, Hou Z, Zhang W, Li M. Piezoelectric Effect and Ignition Characteristics of Coal Mine Gob Roof Collapse. ACS OMEGA 2021; 6:28936-28945. [PMID: 34746585 PMCID: PMC8567394 DOI: 10.1021/acsomega.1c03987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Abstract
Existing studies of coal self-ignition and impact frictional sparks do not provide valid support for the analysis of ignition sources in all cases of methane explosions in the gob. In this paper, the explosion in the gob of the Renlou coal mine is used to investigate the piezoelectric effect and ignition characteristics of roof collapse in identifying a new ignition source of gas explosion. Experimental and theoretical analyses conclude that the piezoelectric effect is produced by quartz, which is the main constituent of the roof sandstone. During the loading process, the piezoelectric effect and compressive strength are key factors in the gathering of free charges on rock tips. During rupture, the rock tip retains a large number of charges, forming a ″point-surface″ effect, which triggers an electron avalanche accompanied by an orange-yellow spark lasting over 22 ms, far exceeding the ionization energy and ignition induction period of methane-air mixtures. The piezoelectric effect and compressive strength of the rock cause the generation of electrical sparks, which is the ignition source of the explosion in the gob of Renlou mine II7322.
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Affiliation(s)
- Ya-nan Wang
- Faculty
of Safety Engineering, China University
of Mining & Technology, Xuzhou, Jiangsu 221116, China
| | - De-ming Wang
- Faculty
of Safety Engineering, China University
of Mining & Technology, Xuzhou, Jiangsu 221116, China
| | - Hai-hui Xin
- State
Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, No. 1 University Road, Xuzhou, Jiangsu 221116, PR China
| | - Yun-fei Zhu
- Department
of Mining Engineering, Shanxi Institute
of Technology, Yangquan 045000, Shanxi, China
| | - Zhenhai Hou
- Faculty
of Safety Engineering, China University
of Mining & Technology, Xuzhou, Jiangsu 221116, China
| | - Wei Zhang
- Faculty
of Safety Engineering, China University
of Mining & Technology, Xuzhou, Jiangsu 221116, China
| | - Min Li
- School
of Resource, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China
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Acoustic Emission Spectroscopy: Applications in Geomaterials and Related Materials. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11198801] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As a non-destructive testing technology with fast response and high resolution, acoustic emission is widely used in material monitoring. The material deforms under stress and releases elastic waves. The wave signals are received by piezoelectric sensors and converted into electrical signals for rapid storage and analysis. Although the acoustic emission signal is not the original stress signal inside the material, the typical statistical distributions of acoustic emission energy and waiting time between signals are not affected by signal conversion. In this review, we first introduce acoustic emission technology and its main parameters. Then, the relationship between the exponents of power law distributed AE signals and material failure state is reviewed. The change of distribution exponent reflects the transition of the material’s internal failure from a random and uncorrelated state to an interrelated state, and this change can act as an early warning of material failure. The failure process of materials is often not a single mechanism, and the interaction of multiple mechanisms can be reflected in the probability density distribution of the AE energy. A large number of examples, including acoustic emission analysis of biocemented geological materials, hydroxyapatite (human teeth), sandstone creep, granite, and sugar lumps are introduced. Finally, some supplementary discussions are made on the applicability of Båth’s law.
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