Magnetochemistry

7 pages, 2284 KiB

Open AccessArticle

by Yixiang Lu, Kai Zhao, Tongyao Zhang and Baojuan Dong

Magnetochemistry 2024, 10(6), 43; https://doi.org/10.3390/magnetochemistry10060043 - 14 Jun 2024

Viewed by 561

Field effect transistors based on few-layered van der Waals transition metal halide (TMH) Nb₃Cl₈ are studied in this work. Few-layered Nb₃Cl₈ exhibits typical N-type semiconducting behavior controlled by a Si gate, with the electrical signal enhancing as [...] Read more.

Field effect transistors based on few-layered van der Waals transition metal halide (TMH) Nb₃Cl₈ are studied in this work. Few-layered Nb₃Cl₈ exhibits typical N-type semiconducting behavior controlled by a Si gate, with the electrical signal enhancing as the thickness increases from 4.21 nm to 16.7 nm. Moreover, we find that the tunability of few-layered Nb₃Cl₈ FETs’ electrical transport properties can be significantly augmented through the use of an ionic liquid gate (or electrical double layer, EDL). This enhancement leads to a substantial increase in the on–off ratio by approximately a factor of

10^{2}

, with the transfer curve modulated into a bipolar fashion. The emergence of such bipolar tunable characteristics in Nb₃Cl₈ FETs serves to enrich the electronic properties within the transition metal halide family, positioning Nb₃Cl₈ as a promising candidate for diverse applications spanning transistors, logic circuits, neuromorphic computing and spintronics. Full article

(This article belongs to the Special Issue Advances in Magnetic Two Dimensional Materials)

► Show Figures

Figure 1

24 pages, 9619 KiB

Open AccessArticle

Nonequivalent Antiferromagnetically Coupled Sublattices Induce Two-Step Spin-Crossover Transitions: Equilibrium and Nonequilibrium Aspects

by Valon Veliu, Orhan Yalçın, Songül Özüm and Rıza Erdem

Magnetochemistry 2024, 10(6), 42; https://doi.org/10.3390/magnetochemistry10060042 - 4 Jun 2024

Viewed by 512

Abstract

As a continuation to the previously published work (Yalçın et al. (2022)), we investigate the equilibrium and nonequilibrium properties of the spin-crossover systems, with a specific focus on the nonequivalent sublattice, and compare these properties with those of the equivalent sublattices. We used [...] Read more.

As a continuation to the previously published work (Yalçın et al. (2022)), we investigate the equilibrium and nonequilibrium properties of the spin-crossover systems, with a specific focus on the nonequivalent sublattice, and compare these properties with those of the equivalent sublattices. We used the lowest approximation of the cluster variation method (LACVM) to derive the static equations for the order parameters of the two sublattices and determine high-spin fraction in relation to temperature and external magnetic field in a spin-crossover system. At a low temperature, the transition from stable high-spin (HS) state where

n_{H S} = 1

occurs in the plateau region, where

n_{H S} = 0.5

for nonequivalent sublattices. The order parameters for non-equivalent sublattices exhibit different states at the transition temperature. Also, we study the nonequilibrium properties of the order parameters and high-spin fraction using the path probability method (PPM). With the current model, we obtain and analyze the relaxation curves for the order parameters

S_{a}

,

S_{b}

, and high-spin fraction. These curves demonstrate the existence of bistability at low temperatures. At the end of this study, we present the flow diagram that shows the order parameters for different temperature values. The diagram exhibits states that are stable, metastable, and unstable. Full article

(This article belongs to the Section Spin Crossover and Spintronics)

► Show Figures

Figure 1

13 pages, 2413 KiB

Open AccessArticle

Magnetically Induced Two-Phonon Blockade in a Hybrid Spin–Mechanical System

by Hong-Yue Liu, Tai-Shuang Yin and Aixi Chen

Magnetochemistry 2024, 10(6), 41; https://doi.org/10.3390/magnetochemistry10060041 - 31 May 2024

Viewed by 399

Abstract

Phonon blockade is an important quantum effect for revealing the quantum behaviors of mechanical systems. For a nitrogen-vacancy center spin strongly coupled to a mechanical resonator via the second-order magnetic gradient, we show that the qubit driving can lead to the implementation of [...] Read more.

Phonon blockade is an important quantum effect for revealing the quantum behaviors of mechanical systems. For a nitrogen-vacancy center spin strongly coupled to a mechanical resonator via the second-order magnetic gradient, we show that the qubit driving can lead to the implementation of the two-phonon blockade, while the usual mechanical driving only allows for the appearance of a single-phonon blockade. As a signature, we investigate three-phonon antibunching with a simultaneous two-phonon bunching process by numerically calculating the second-order and third-order correlation functions. We also analyze in detail the influence of the system parameters (including the qubit driving strength, the dephasing rate of the qubit, as well as the thermal phonon number) on the quality of the two-phonon blockade effect. Our work provides an alternative method for extending the concept of a phonon blockade from a single phonon to multiphonon. It is of direct relevance for the engineering of multiphonon quantum coherent devices and thus has potential applications in quantum information processing. Full article

► Show Figures

Figure 1

21 pages, 3233 KiB

Open AccessReview

The Catalytic Activity of Magnetic Surfaces

by Ian Shuttleworth

Magnetochemistry 2024, 10(6), 40; https://doi.org/10.3390/magnetochemistry10060040 - 28 May 2024

Viewed by 570

Abstract

High-performance catalysts for the oxygen reduction and hydrogen evolution reactions (ORR and HER, respectively) are highly sought-after, particularly with the commitment of numerous agencies to the removal of conventional gas vehicles in the next few decades. Surprisingly little focus has been placed on [...] Read more.

High-performance catalysts for the oxygen reduction and hydrogen evolution reactions (ORR and HER, respectively) are highly sought-after, particularly with the commitment of numerous agencies to the removal of conventional gas vehicles in the next few decades. Surprisingly little focus has been placed on the development of magnetic models to describe these systems. The current work will review the current understanding of surface heterogeneous catalysis across select magnetic surfaces, with attention focused on studies involving extended surfaces, which inherently are more accessible to fundamental analysis than the more applied nanoparticle systems. However, even the most up-to-date magnetic variants of this theory have focused on the tight binding limit of the d-band model. In this limit, the reactivity of the surface is governed by the position of the center of the d-band, and the model does not account for the higher moments of the d-band, such as the width, asymmetry, and modality. A summary of the theory supporting this analysis will be presented, along with a summary of the current literature on this level of analysis. The review will then conclude with a discussion of suggested directions for future investigations. Full article

► Show Figures

Graphical abstract

8 pages, 2225 KiB

Open AccessArticle

Magnetically Induced Near-Infrared Circularly Polarized Electroluminescence from an Achiral Perovskite Light-Emitting Diode

by Yoshitane Imai, Ryo Amasaki, Yoshihiko Yanagibashi, Seika Suzuki, Ryuta Shikura and Shigeyuki Yagi

Magnetochemistry 2024, 10(6), 39; https://doi.org/10.3390/magnetochemistry10060039 - 28 May 2024

Viewed by 641

Abstract

Circularly polarized electroluminescent devices are conventionally fabricated by incorporating an optically active chiral luminophore into their emission layer. Herein, we developed a circularly polarized perovskite light-emitting diode (PeLED) system with an optically inactive perovskite luminophore that can emit near-infrared circularly polarized electroluminescence (CPEL) [...] Read more.

Circularly polarized electroluminescent devices are conventionally fabricated by incorporating an optically active chiral luminophore into their emission layer. Herein, we developed a circularly polarized perovskite light-emitting diode (PeLED) system with an optically inactive perovskite luminophore that can emit near-infrared circularly polarized electroluminescence (CPEL) upon application of an external magnetic field. The magnitude of the magnetic CPEL (g_MCPEL) was in the order of 10⁻³ in the near-infrared wavelength range of 771–773 nm. Although the Pb perovskite quantum dots were achiral, the rotation direction of the CPEL of the magnetic circularly polarized PeLED system was successfully reversed by switching the Faraday geometry of the applied magnetic field. The use of achiral luminophores exhibiting magnetic-field-induced CPEL represents a new approach for the development of circularly polarized electroluminescent devices. Full article

(This article belongs to the Section Applications of Magnetism and Magnetic Materials)

► Show Figures

Figure 1

20 pages, 5977 KiB

Open AccessArticle

New Branched Iron(III) Complexes in Fluorescent Environment Created by Carbazole Moieties: Synthesis and Structure, Static Magnetic and Resonance Properties

by Denis V. Starichenko, Valerya E. Vorobeva, Matvey S. Gruzdev, Ulyana V. Chervonova, Nataliya G. Bichan, Aleksander V. Korolev and Ivan V. Yatsyk

Magnetochemistry 2024, 10(6), 38; https://doi.org/10.3390/magnetochemistry10060038 - 21 May 2024

Viewed by 589

Abstract

The branched complexes of Schiff bases with various iron(III) salts, named G2-[L₂Fe]⁺A⁻ (A⁻ is NO₃⁻, Cl⁻, PF₆⁻), were synthesized using the condensation reaction between carbazole derivatives of salicylic aldehyde [...] Read more.

The branched complexes of Schiff bases with various iron(III) salts, named G2-[L₂Fe]⁺A⁻ (A⁻ is NO₃⁻, Cl⁻, PF₆⁻), were synthesized using the condensation reaction between carbazole derivatives of salicylic aldehyde and N’-ethylethylenediamine and characterized by various spectroscopic methods (GPC, IR, ¹H NMR, UV/Vis). The studies revealed that the coordination of the two ligand molecules to metal occurs through the nitrogen ions and oxygen atom of azomethine to form a homoleptic system. All the synthesized coordination compounds were examined for their thermal, optical, and magnetic features. Static magnetic measurements showed that only G2-[L₂Fe]Cl was in a single-phase HS state, whereas the Fe(III) ions of G2-[L₂Fe]NO₃ and G2-[L₂Fe]PF₆ at room temperatures were in mixed low-spin (LS, S = 1/2) and high-spin (HS, S = 5/2) states: 58.9% LS/41.1% HS for G2-[L₂Fe]NO₃, 56.1% LS and 43.9% HS for G2-[L₂Fe]PF₆. All G2-[L₂Fe]⁺A⁻ complexes demonstrate antiferromagnetic exchange interactions between neighboring Fe(III) ions. The ground spin state at 2.0 K revealed a Brillouin contribution from non-interacting LS ions and a proportion of the HS Fe(III) ions not participating in AFM interactions: 57%, 18%, and 16% for G2-[L₂Fe]Cl, G2-[L₂Fe]NO₃ and G2-[L₂Fe]PF₆, respectively. EPR measurements confirmed the presence of magnetically active HS and LS states of Fe(III) ions and made it possible to distinguish two HS types-with strong low-symmetry (I-type) and weak, distorted octahedral environments (II-type). It was shown that G2-[L₂Fe]⁺A⁻ complexes are magnetically inhomogeneous and consist of two magnetic sub-lattices: AFM-correlated chains in layers from the I-type HS Fe(III) centers and dynamic short-range AFM ordered LS/II-type HS Fe(III) centers in the paramagnetic phase located between the layers. Full article

(This article belongs to the Special Issue Functional Magnetic Nanomaterials and Nanostructures: Properties and Applications)

► Show Figures

Figure 1

9 pages, 3012 KiB

Open AccessArticle

The Electric Properties of the Magnetopause Boundary Layer

by Lai Gao, Chao Shen, Yong Ji, Yufei Zhou and Yulia V. Bogdanova

Magnetochemistry 2024, 10(6), 37; https://doi.org/10.3390/magnetochemistry10060037 - 21 May 2024

Viewed by 491

Abstract

The magnetopause plays a pivotal role in the coupling among solar wind, the magnetosheath, and the magnetosphere. By analyzing magnetopause crossing events using MMS, we reveal a local non-neutrality of electric charges in the magnetopause boundary layer and the associated electric field. There [...] Read more.

The magnetopause plays a pivotal role in the coupling among solar wind, the magnetosheath, and the magnetosphere. By analyzing magnetopause crossing events using MMS, we reveal a local non-neutrality of electric charges in the magnetopause boundary layer and the associated electric field. There are two types of electric structures. In one group, which typically occurs on the dusk side, the electric field directs towards the Earth. In the other, which generally occurs on the day side, the field directs away from the Earth. The spatial extent of this electric non-neutrality spans approximately 600 km, which is at the scale of ion gyrational motion. These findings provide valuable insights into the fine structures of the magnetopause and the coupling between the magnetosheath and the magnetosphere. Full article

(This article belongs to the Special Issue New Insight into the Magnetosheath)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Magnetochemistry, Volume 10, Issue 6 (June 2024) – 7 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI