Frustration Effects Research Articles

Cooperativity and Frustration Effects (or Lack Thereof) in Polarizable and Non-polarizable Force Fields.

Understanding cooperativity and frustration is crucial for studying biological processes such as molecular recognition and protein aggregation. Force fields have been extensively utilized to explore cooperativity in the formation of protein secondary structures and self-assembled systems. Multiple studies have demonstrated that polarizable force fields provide more accurate descriptions of this phenomenon compared to fixed-charge pairwise nonpolarizable force fields, thanks to the incorporation of polarization effects. In this study, we assess the performance of the AMOEBA polarizable force field and the AMBER and OPLS nonpolarizable pairwise force fields in capturing positive and negative cooperativity recently explored in neutral and charged molecular clusters using density functional theory. Our findings show that polarizable and nonpolarizable force fields qualitatively reproduce the relative cooperativity observed in electron structure calculations. However, AMBER and OPLS fail to describe absolute cooperativity. In contrast, AMOEBA accounts for the absolute cooperativity by considering interactions beyond pairwise interactions. According to the energy decomposition analysis, it is observed that the electrostatic interactions calculated with the AMBER and OPLS force fields seem to play an important and counterintuitive role in reproducing the adiabatic interaction energies calculated with density functional theory. However, it is important to note that these force fields, due to their nature, do not explicitly incorporate many-body effects, which limits their ability to accurately describe cooperativity. On the other hand, frustration in polarizable and nonpolarizable force fields is caused by changes in bond stretching and angle bending terms of the building blocks when they are forming a complex.

Mechanisms of linear control of exchange bias in Fe/FeO bilayer

The microscopic nature of pinning uncompensated moment interface, how it is pinned by an antiferromagnet, and how the mechanism with this coupling drives exchange bias remain outstanding challenges. In this work, the Fe/FeO ferromagnet/antiferromagnet bilayer with an ultrathin FeO layer is modeled and the correlation between exchange bias and microscopically uncompensated antiferromagnetic magnetization is studied, based on first-principles calculations and modified Monte-Carlo simulations, where spin energies are exactly calculated and energy barriers are detectable to avoid the occurrence of unphysical tunneling during spin reversals. The linear dependence of exchange bias on uncompensated antiferromagnetic magnetization in Fe/FeO bilayer experimentally is reproduced and interpreted by exploring the monolayer-resolved magnetization behavior in the FeO layer, which depends on antiferromagnetic anisotropy, cooling field, fraction of Fe atoms permeated in the FeO layer, and magnetic frustration effect. It is evidenced that this linear dependence requires plenty of controllable pinning uncompensated antiferromagnetic spins located in the layer depths close to but not in contact with the ferromagnetic layer.

Surveying an energy landscape

We derive a formula that expresses the density of states of a system with continuous degrees of freedom as a function of microcanonical averages of squared gradient and Laplacian of the Hamiltonian. This result is then used to propose a novel flat-histogram Monte Carlo algorithm, which is tested on a three-dimensional system of interacting Lennard-Jones particles, the O(n) vector spin model on hypercubic lattices in D = 1 to 5 dimensions, and the O(3) Heisenberg model on a triangular lattice featuring frustration effects.

Escape rate in ac SQUID on josephson junction based on single- and multi-band superconductors in thermal activation regime

The escape rate of S→R switching (from superconducting S state to unstable resistive R state) in an ac SQUID with Josephson junction based on single- and multi-band superconductors is investigated by taking the frustration effects in a multi-band superconducting state into account. Using the effective critical current approach, it is shown that the escape rate in thermal activation regime can manifest qualitative features caused by the frustration effects in two- and three-band superconductors.

Ambition‐driven aggression in response to significance‐threatening frustration

AbstractConceptualizing aggression as elicited by the significance‐reducing effects of frustration, and ambition as reflecting the quest for significance, we tested the role of ambition in the frustration–aggression relationship. Study 1 (N = 249) found that ambitious individuals are more sensitive to significance‐threatening frustration. Study 2 (N = 413) found that significance‐reducing (vs. non‐reducing) frustration leads to more aggressiveness through significance loss and that ambitious individuals react to significance‐reducing frustration more aggressively. Study 3 (N = 248) replicated this relation and demonstrated that the aggressiveness of ambitious individuals in reaction to significance‐reducing frustration is not related to their trait aggression. Study 4 (N = 196) showed that it is also unrelated to their trait‐level frustration, and Study 5 (N = 172) replicated the relation between ambition and aggression consequent significance‐reducing frustration with a different methodology. This research supports the notion that an aggressive response to frustration pertains to the significance‐reducing nature of the frustration, and that ambition is a moderator of this relation.

Near Room-Temperature Intrinsic Exchange Bias in an Fe Intercalated ZrSe2 Spin Glass.

Some magnetic systems display a shift in the center of their magnetic hysteresis loop away from zero field, a phenomenon termed exchange bias. Despite the extensive use of the exchange bias effect, particularly in magnetic multilayers, for the design of spin-based memory/electronics devices, a comprehensive mechanistic understanding of this effect remains a longstanding problem. Recent work has shown that disorder-induced spin frustration might play a key role in exchange bias, suggesting new materials design approaches for spin-based electronic devices that harness this effect. Here, we design a spin glass with strong spin frustration induced by magnetic disorder by exploiting the distinctive structure of Fe intercalated ZrSe2, where Fe(II) centers are shown to occupy both octahedral and tetrahedral interstitial sites and to distribute between ZrSe2 layers without long-range structural order. Notably, we observe behavior consistent with a magnetically frustrated and multidegenerate ground state in these Fe0.17ZrSe2 single crystals, which persists above room temperature. Moreover, this magnetic frustration leads to a robust and tunable exchange bias up to 250 K. These results not only offer important insights into the effects of magnetic disorder and frustration in magnetic materials generally, but also highlight as design strategy the idea that a large exchange bias can arise from an inhomogeneous microscopic environment without discernible long-range magnetic order. In addition, these results show that intercalated TMDs like Fe0.17ZrSe2 hold potential for spintronic technologies that can achieve room temperature applications.

Influence of Frustration Effects on the Critical Current of DC SQUID

In this paper, we conducted the calculation of the critical current of DC SQUID based on the Josephson junction on a multi-band superconductor with frustration effect. It is shown that the critical current of DC SQUID on the frustrated multi-band superconductor with a small geometrical inductance of the loop is determined by the supercurrent amplitude in different channels and by the external magnetic field. In the case of a DC SQUID with high inductance, frustration effects can be ignored.

The effects of reward and frustration on the task performance of autistic children and adolescents

BackgroundAutistic individuals often exhibit social communication and socio-emotional styles that may interfere with achieving social and academic outcomes. At a more specific level, they may perform differently in various social and academic tasks due to different modes of processing rewards or unpleasant experiences (e.g., frustrating events). AimThe present experiment examines how rewards and frustration affect the task performance of autistic children and adolescents Methods and proceduresAn affective Posner task was applied to introduce rewards and induce frustration. Forty-four autistic children and adolescents and forty-four typically developing (TD) peers participated in this study Outcomes and resultsResults showed that presenting social and non-social rewards resulted in shorter reaction times and lower error rates in autistic participants, but not in their TD peers. While frustration increased error rates in both autistic and TD individuals, the effect was more pronounced in the autistic group. Conclusions and implicationsSocial and non-social rewards help the performance of autistic children and adolescents, whereas frustration (induced through unpredictable feedback) significantly interferes with their task performance. Therefore, receiving two types of rewards and providing predictable feedback may help to improve interventions designed to optimize task performance for autistic children and adolescents.

The Effect of Frustration on an Employee’s Earned Salary: National Revenue Mobilisation Allocation and Fiscal Commission v. Johnson in Perspective

The Effect of Frustration on an Employee’s Earned Salary: National Revenue Mobilisation Allocation and Fiscal Commission v. Johnson in Perspective

Magnetism in frustrated Kondo and non-Kondo intermetallics: CeInCu2 versus NdInCu2

Single crystalline intermetallics ${\mathrm{CeInCu}}_{2}$ and ${\mathrm{NdInCu}}_{2}$, where the rare earth ions occupy geometrically frustrated fcc lattice of Heusler-type structure, have been studied comparatively to shed light on the ground-state magnetism derived from Kondo physics and/or spin frustration competing with the Ruderman-Kittel-Kasuya-Yosida interaction. ${\mathrm{CeInCu}}_{2}$ is distinct from ${\mathrm{NdInCu}}_{2}$ due to the significant Kondo effect that is absent in the latter. They order antiferromagnetically at ${T}_{N}\phantom{\rule{0.16em}{0ex}}\ensuremath{\approx}\phantom{\rule{0.16em}{0ex}}1.4$ and 2.0 K with large paramagnetic Curie-Weiss temperature of $\ensuremath{-}35.4$ K and $\ensuremath{-}41.1$ K, respectively. The electronic specific-heat coefficient $\ensuremath{\gamma}$ = $C/T$ ($T\phantom{\rule{0.16em}{0ex}}\ensuremath{\rightarrow}\phantom{\rule{0.16em}{0ex}}0$) = 870 mJ ${\mathrm{mol}}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}$ in ${\mathrm{CeInCu}}_{2}$ is significantly enhanced, much larger than 180 mJ ${\mathrm{mol}}^{\ensuremath{-}1}\phantom{\rule{4pt}{0ex}}{\mathrm{K}}^{\ensuremath{-}2}$ of the latter that is also enhanced albeit its non-Kondo nature. For both compounds, the Kadowaki-Woods ratio deviates greatly from the standard value expected from a Kramers doublet ground state, which, however, can be restored if one considers a smaller but still sizable $\ensuremath{\gamma}$ estimated from the paramagnetic state. Likewise, the Kondo temperature of ${\mathrm{CeInCu}}_{2}$ is revised to be ${T}_{K}\phantom{\rule{4pt}{0ex}}\ensuremath{\approx}$ 13 K that is double the literature values, manifesting a major effect of spin frustration to low-temperature thermodynamics beyond the Kondo physics. Similarities between the two compounds is also noticed in their temperature-field phase diagrams in spite of their thermodynamic distinctions in the thermal expansion and the Gr\"uneisen ratio, which are much more sensitive to Kondo hybridization than to geometrical frustration.

The Effects of Patient-Centered Communication on Emotional Health: Examining the Roles of Self-Efficacy, Information Seeking Frustration, and Social Media Use

The existing literature on the direct association between patient-centered communication (PCC) and emotional well-being often demonstrates inconsistent results. To explain such inconsistency, it is important to explore the mediating and moderating mechanisms underlying this relationship. Built upon the communication pathways model, this study empirically analyzed the Health Information National Trends Survey 5 Cycle 3 dataset (N = 4,709) and tested a moderated mediation model that links PCC to emotional health via information-seeking self-efficacy, with an additional assessment of the moderating effects of information-seeking frustration and social media use. The findings showed that PCC was positively related to emotional health. Also, PCC was indirectly associated with emotional health through information-seeking self-efficacy. In addition, information-seeking frustration and social media use weakened the association between PCC and information-seeking self-efficacy. Furthermore, the indirect path from PCC to emotional health through information-seeking self-efficacy was conditional on both information-seeking frustration and social media use. Important theoretical and practical implications are also discussed.

Magnetoelastic transition and negative thermal expansion of Fe2Hf0.83Ta0.17 ribbons

In this work, the magnetocaloric effect and negative thermal expansion in melt-spun Fe2Hf0.83Ta0.17 Laves phase alloys were studied. Compared to arc-melted alloys, which undergo a first-order magnetoelastic transition from the ferromagnetic to the antiferromagnetic phase, melt-spun alloys exhibit a second-order transition. For Fe2Hf0.83Ta0.17 ribbons, we observed a large volumetric coefficient of negative thermal expansion of −19 × 10−6 K−1 over a wide temperature range of 197 – 297 K and a moderate adiabatic temperature change of 0.7 K at 290 K for a magnetic field change of 1.5 T. The magnetic field dependence of the transition temperature (dTt/dµ0H = 4.4 K/T) for the melt-spun alloy is about half that of the arc-melted alloy (8.6 K/T). The origin of second-order phase transition of the melt-spun alloy is attributed to the partially suppressed frustration effect, which is due to the atomic disorder introduced by the rapid solidification.

Role conflict, need frustration and supervisor support: a moderated-mediation model of employee voice and silence

PurposeDrawing on the conservation of resources theory, the purpose of this paper is to examine whether role conflict is associated with frustration of employees’ basic needs and whether need frustration is associated with withdrawal in the form of reduced voice and increased silence. This paper also investigates if supervisor support mitigates potential detrimental outcomes of need frustration.Design/methodology/approachIn this survey-based study, 201 full-time employees participated. Self-reports regarding voice and silence behaviors at work were collected as were perceptions of role conflict, need frustration and supervisor support.FindingsThe results of this study support the proposed moderated mediation relationships for both employee voice and silence behaviors. Specifically, need frustration mediates the relationship between role conflict and the two outcome variables. Perceived supervisor support moderates the path between need frustration and both voice and silence behaviors.Practical implicationsEmployees are an organization’s first line of defense against potential accidents, inefficiencies and other organizational crises. When they perceive their needs are not met and they are not supported by their supervisors, employees are likely to seek to protect themselves from further resource loss by withholding feedback even if such feedback may enhance organizational effectiveness and prevent organizational crises.Originality/valueGiven that voice and silence are not opposites of each other, it is important to study both in a single study, as this study does. This study proposes and tests a heretofore untested explanation for the relationship between role conflict and voice and silence. The authors identify a buffer with potential to mitigate the negative effects of need frustration.

Interactive effects of basic psychological need satisfaction and frustration on career calling among chinese kindergarten teachers: a person-centered approach

Interactive effects of basic psychological need satisfaction and frustration on career calling among chinese kindergarten teachers: a person-centered approach

Effects of parity, frustration, and stochastic fluctuations on integrated conceptual information for networks with two small-sized loops

This paper presents an evaluation of the system-level integrated conceptual information of a major complex for a small-scale network containing two loops in accordance with the integrated information theory 3.0 framework. We focus on the following parameters characterizing the system model: (1) number of nodes in the loop, (2) frustration of the loop, and (3) temperature controlling the stochastic fluctuation of the state transition. Effects of these parameters on the integrated conceptual information and conditions for major complexes formed by a single loop, rather than the entire network, are investigated. Our first finding is that parity of the number of nodes forming a loop has a strong effect on the integrated conceptual information. For loops with an even number of nodes, the number of concepts tends to decrease, and the integrated conceptual information becomes smaller. Our second finding is that a major complex is more likely to be formed by a small number of nodes under small stochastic fluctuations. On the other hand, the entire network can easily become a major complex under larger stochastic fluctuations, and this tendency can be reinforced by frustration. It is also shown that, although counterintuitive, the integrated conceptual information can be maximized in the presence of stochastic fluctuations. These results suggest that even when several small subnetworks are connected by only a few connections, such as a bridge, the entire network may become a major complex by introducing some stochastic fluctuations and by frustrating loops with an even number of nodes.

Antiferromagnetic Ising model with frustration on Graphenylene lattice

Frustration effects due to competition between nearest-neighbor and next-nearest-neighbor spins interaction on the graphenylene lattice, also known as biphenylene carbon lattice, were investigated by Monte Carlo simulations. We identified two possible phases from our results of the entropy at zero temperature, namely an ordered spin glass and other an antiferromagnetic phase. Despite the complexity of the lattice, a finite size scaling analysis for the antiferromagnetic regime shows that it can be classified into the same universality class of the usual Ising model. The canonical probability distribution as a function of the spin glass order parameter was computed and the continuous spin glass phase transition confirmed.

Influence of Anharmonic and Frustration Effects on Josephson Phase Qubit Characteristics

This study is devoted to the investigation of the Josephson phase qubit spectrum considering the anharmonic current-phase relation of the junction. The change in energy difference in the spectrum of phase qubits based on single-band/multiband Josephson junctions is also analyzed. It was shown that the presence of the anharmonic term in the current-phase relation and frustration effects in the junction electrodes leads to changing effective plasma frequencies in the different cases and results in an energy spectrum.

Strong spin frustration and magnetism in kagomé antiferromagnets LnCu3(OH)6Br3 (Ln = Nd, Sm, and Eu)

To study the effects of lanthanide ions on the geometrically frustrated antiferromagnets and their magnetic properties, we grew high-quality single crystals of LnCu3(OH)6Br3 (Ln = Nd, Sm, and Eu) by hydrothermal method and studied their crystal structures and magnetic properties. The refinements of the crystal structure referred to the powder x-ray diffraction data show that LnCu3(OH)6Br3 adopt a Kapellasite-type layer structure, which is isostructural to their chlorine analogue. Magnetic susceptibilities demonstrate that LnCu3(OH)6Br3 have strong antiferromagnetic coupling and a pronounced magnetic frustration effect. Magnetization measurements indicate canted antiferromagnetic ordering of Cu2+ ions around 16 K within the kagomé plane and weak ferromagnetic coupling. Moreover, shoulder-like anomalies in specific heat around 16 K could be a signature of emergent of magnetic ordering. The low-temperature negative magnetization and specific heat of LnCu3(OH)6Br3 (Ln = Nd, Sm, and Eu) indicate that Ln 3+ ions induce more exotic magnetic ground state properties.

Short-range order and increased transition temperature in LiVO2 with weakened trimer frustration

Vanadium atoms in layered LiVO2 form in-plane periodic vanadium trimers at low temperatures, but the trimers appear randomly in the stacking direction because there are many trimer configurations with comparable lattice energy. We detailed an original modeling scheme to represent glassy states with a completely disordered trimer configuration in the stacking structure. Through PDF analysis using this model, we show that the synthesis method can yield two types of low-temperature stacking structures: a completely disordered stacking structure and a short-range order in the stacking structure. The phase transition temperature of the former sample is about 15 K lower than that of the latter. We discuss that this is due to the strong trimer frustration that appears in the sample without short-range order, which suppresses the phase transition temperature, similar to the frustration effect in conventional spin systems.

From sandwich complexes to dendrimers: journey toward applications to sensing, molecular electronics, materials science, and biomedicine.

This review links various areas of inorganic chemistry around the themes developed by our research group during the last four decades. It is firstly based on the electronic structure of iron sandwich complexes, showing how the metal electron count dictates their reactivities, with various applications (via C-H activation, C-C bond formation) as reducing and oxidizing agents, redox and electrocatalysts and precursors of dendrimers and catalyst templates through bursting reactions. Various electron-transfer processes and consequences are explored, including the influence of the redox state on the acidity of robust ligands and the possibility to iterate in situ C-H activation and C-C bond formation to build arene-cored dendrimers. Examples of how these dendrimers are functionalized are illustrated using the cross olefin metathesis reactions, with application to the synthesis of soft nanomaterials and biomaterials. Mixed and average valence complexes give rise to remarkable subsequent organometallic reactions, including the salt influence on these reactions. The stereo-electronic aspect of these mixed valencies is pointed out in star-shaped multi-ferrocenes with a frustration effect and other multi-organoiron systems, with the perspective of understanding electron-transfer processes among dendrimer redox sites involving electrostatic effects and application to redox sensing and polymer metallocene batteries. Dendritic redox sensing is summarized for biologically relevant anions such as ATP2- with supramolecular exoreceptor interactions at the dendrimer periphery in parallel with the seminal work on metallocene-derived endoreceptors by Beer's group. This aspect includes the design of the first metallodendrimers that have applications in both redox sensing and micellar catalysis with nanoparticles. These properties provide the opportunity to summarize the biomedical (mostly anticancer) applications of ferrocenes, dendrimers and dendritic ferrocenes in biomedicine (in particular the contribution from our group, but not only). Finally, the use of dendrimers as templates for catalysis is illustrated with numerous reactions including C-C bond formation, click reactions and H2 production reactions.