Spin Frustration Drives Exchange Bias Sign Crossover in CoFe2O4–Cr2O3 Nanocomposites

Testa‐Anta, Martín; Rivas‐Murias, B.; Salgueiriño, Verónica

doi:10.1002/adfm.201900030

Cited by 22 publications

(10 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The loops show positive EB fields of 0.18 and 1.1 mT at 323 and 232 K, respectively. The absence of perpendicular EB and the presence of in-plane EB indicate that the boundary magnetization in B-doped chromia tends to tilt away from the c -axis in agreement with recent findings in CoFe 2 O 4 –Cr 2 O 3 nanocomposites 28 . There is strong support for this interpretation from T -dependent spin-resolved inverse photoemission shown in Figs.…”

Section: Resultssupporting

confidence: 90%

Voltage controlled Néel vector rotation in zero magnetic field

et al. 2021

View full text Add to dashboard Cite

Multi-functional thin films of boron (B) doped Cr2O3 exhibit voltage-controlled and nonvolatile Néel vector reorientation in the absence of an applied magnetic field, H. Toggling of antiferromagnetic states is demonstrated in prototype device structures at CMOS compatible temperatures between 300 and 400 K. The boundary magnetization associated with the Néel vector orientation serves as state variable which is read via magnetoresistive detection in a Pt Hall bar adjacent to the B:Cr2O3 film. Switching of the Hall voltage between zero and non-zero values implies Néel vector rotation by 90 degrees. Combined magnetometry, spin resolved inverse photoemission, electric transport and scanning probe microscopy measurements reveal B-dependent TN and resistivity enhancement, spin-canting, anisotropy reduction, dynamic polarization hysteresis and gate voltage dependent orientation of boundary magnetization. The combined effect enables H = 0, voltage controlled, nonvolatile Néel vector rotation at high-temperature. Theoretical modeling estimates switching speeds of about 100 ps making B:Cr2O3 a promising multifunctional single-phase material for energy efficient nonvolatile CMOS compatible memory applications.

show abstract

Section: Resultssupporting

confidence: 90%

Voltage controlled Néel vector rotation in zero magnetic field

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Despite the low price, low toxicity, good mechanical properties, and high magnetization saturation of cobalt ferrite [ 1,23 ] —CoFe 2 O 4 (≈60 emu g –1 ), its high coercivity (higher than ≈ 200 Oe) is an important restrictive factor in certain applications like electromagnetic shielding, magnetic filtering, actuators or security papers. [ 20,24 ] Fe 3 O 4 can be a solution for a successful magnetic impregnation process due to its biocompatibility, low toxicity in human body, and stable room‐temperature superparamagnetic response.…”

Section: Introductionmentioning

confidence: 99%

A Facile Nanoimpregnation Method for Preparing Paper‐Based Sensors and Actuators

Brito‐Pereira

Tubío

Lanceros‐Méndez

et al. 2021

Adv Materials Technologies

View full text Add to dashboard Cite

Paper‐based advanced functional materials have become the focus of intense research in recent years. Particularly, magnetic papers show strong potential for applications in a wide range of 4.0 technologies including communication, magnetic sensing, electromagnetic filtering, magnetic‐based health care tools, point‐of‐care microfluidic devices, and security. In situ and lumen‐loading, the main methods to prepare magnetoactive papers, have problems such as the rigorous reaction conditions, hard control of deposition location, decreased tensile strength, poor retention of magnetic nanoparticles, or the obligation to perform the magnetic impregnation during the papermaking process, that hinder their applicability. Those issues are addressed in the present work, in which ≈20 nm Fe3O4 nanoparticles are hydrothermally synthesized and later incorporated in a wax‐based home‐made cartridge and nanoimpregnated into paper by a thermal process leading to a magnetic paper with improved stress and strain at rupture and Young's modulus, 30 MPa, 4.5%, and 2 GPa, respectively, when compared to neat paper, 15 MPa, 3.5%, and ≈1 GPa, respectively. Additionally, the reported magnetic impregnation method provides the paper with a 0.2 emu g–1 magnetic saturation, allowing it to work as a bending actuator with a bending of 12 mm at an applied magnetic field of 105 mT.

show abstract

“…Raman spectroscopy analysis was used further to investigate the state change of Fe and Co before and during the peroxidase-like reaction Figure h displays that several bands could be detected at 181, 321, 471, 517, and 661 cm –1 in Raman spectra before reaction.…”

Section: Resultsmentioning

confidence: 99%

Co₃O₄/CoFe₂O₄ Hollow Nanocube Multifunctional Nanozyme with Oxygen Vacancies for Deep-Learning-Assisted Smartphone Biosensing and Organic Pollutant Degradation

Shao-juan

et al. 2023

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

Although the application of nanozymes has been widely studied, it is still a huge challenge to develop highly active and multifunctional nanozyme catalysts with a wider application prospect. Co 3 O 4 /CoFe 2 O 4 hollow nanocubes (HNCs) with oxygen vacancies were proposed in this study, which had a porous oxide heterostructure with CoFe 2 O 4 as the core and Co 3 O 4 as the shell. The Co 3 O 4 /CoFe 2 O 4 HNCs had three enzyme activities: peroxidase-like, oxidase-like, and catalase-like. Combining XPS depth profiling with density functional theory (DFT), the catalytic mechanism of peroxidase-like activity was explored in depth, which was mainly originated from •OH produced by the synergistic effect between the outer oxygen and inner oxygen and electron transfer between Co and Fe. A colorimetry/smartphone dual sensing platform was designed based on the peroxidase-like activity. Especially, a multifunctional intelligent sensing platform based on deep learning-YOLO v3 algorithm-assisted smartphone was constructed to realize real-time and rapid in situ detection of L-cysteine, norfloxacin, and zearalenone. Surprisingly, the detection limit of norfloxacin was low at 0.015 μM, which was better than that of the newly published detection method in the field of nanozymes. Meanwhile, the detection mechanism of L-cysteine and norfloxacin was successfully investigated by in situ FTIR. In fact, it also showed outstanding applications in detecting L-cysteine in the food environment and norfloxacin in drugs. Furthermore, Co 3 O 4 /CoFe 2 O 4 HNCs also could degrade 99.24% of rhodamine B, along with good reusability even after 10-cycle runs. Therefore, this work provided an in-depth understanding of the synergistic effect between the outer and inner oxygen in the reaction mechanism and an efficient method for establishing a deep-learning-assisted intelligent detection platform. In addition, this research also offered a good guideline for the further development and construction of nanozyme catalysts with multienzyme activities and multifunctional applications.

show abstract

Spin Frustration Drives Exchange Bias Sign Crossover in CoFe₂O₄–Cr₂O₃ Nanocomposites

Cited by 22 publications

References 44 publications

Voltage controlled Néel vector rotation in zero magnetic field

Voltage controlled Néel vector rotation in zero magnetic field

A Facile Nanoimpregnation Method for Preparing Paper‐Based Sensors and Actuators

Co₃O₄/CoFe₂O₄ Hollow Nanocube Multifunctional Nanozyme with Oxygen Vacancies for Deep-Learning-Assisted Smartphone Biosensing and Organic Pollutant Degradation

Contact Info

Product

Resources

About

Spin Frustration Drives Exchange Bias Sign Crossover in CoFe2O4–Cr2O3 Nanocomposites

Cited by 22 publications

References 44 publications

Voltage controlled Néel vector rotation in zero magnetic field

Voltage controlled Néel vector rotation in zero magnetic field

A Facile Nanoimpregnation Method for Preparing Paper‐Based Sensors and Actuators

Co3O4/CoFe2O4 Hollow Nanocube Multifunctional Nanozyme with Oxygen Vacancies for Deep-Learning-Assisted Smartphone Biosensing and Organic Pollutant Degradation

Contact Info

Product

Resources

About

Spin Frustration Drives Exchange Bias Sign Crossover in CoFe₂O₄–Cr₂O₃ Nanocomposites

Co₃O₄/CoFe₂O₄ Hollow Nanocube Multifunctional Nanozyme with Oxygen Vacancies for Deep-Learning-Assisted Smartphone Biosensing and Organic Pollutant Degradation