Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

González, Javier; Andrés, J. P.; Antón, Ricardo López; Toro, J. A. De; Normile, P. S.; Muniz, Pablo Rodrigues; Riveiro, José Manuel Suárez; Nogués, J.

doi:10.1021/acs.chemmater.7b00868

Cited by 40 publications

(25 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moments tend to be more aligned in the magnetic field direction and vice-versa for higher temperature 52 , 53 .The magnetization versus applied field recorded at 60 K for both NF and FN as shown in Fig. 7 c,d perfectly exhibits an EB phenomenon with an expansion in the coercive field (H c ) and shifting of the hysteresis loop with a field magnitude referred to as the EB field (H eb ) 19 , 54 . Interestingly, the shifting of M-H loop is observed along the negative field 20 , 54 , 55 for inverted NF with an EB field H eb = − 329.43 Oe, while the M–H loop is shifted along the positive field 15 , 56 , 57 with H eb = + 126 Oe for FN system.…”

Section: Resultsmentioning

confidence: 90%

“…7 c,d perfectly exhibits an EB phenomenon with an expansion in the coercive field (H c ) and shifting of the hysteresis loop with a field magnitude referred to as the EB field (H eb ) 19 , 54 . Interestingly, the shifting of M-H loop is observed along the negative field 20 , 54 , 55 for inverted NF with an EB field H eb = − 329.43 Oe, while the M–H loop is shifted along the positive field 15 , 56 , 57 with H eb = + 126 Oe for FN system. The variation of H eb with temperature for both the CS nanostructure is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

Tsopoe

Borgohain

Fopase

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Exchange bias (EB) of magnetic nanoparticles (MNPs) in the nanoscale regime has been extensively studied by researchers, which have opened up a novel approach in tuning the magnetic anisotropy properties of magnetic nanoparticles (MNPs) in prospective application of biomedical research such as magnetic hyperthermia. In this work, we report a comparative study on the effect of magnetic EB of normal and inverted core@shell (CS) nanostructures and its influence on the heating efficiency by synthesizing Antiferromagnetic (AFM) NiO (N) and Ferrimagnetic (FiM) Fe3O4 (F). The formation of CS structures for both systems is clearly authenticated by XRD and HRTEM analyses. The magnetic properties were extensively studied by Vibrating Sample Magnetometer (VSM). We reported that the inverted CS NiO@Fe3O4 (NF) MNPs have shown a greater EB owing to higher uncompensated spins at the interface of the AFM, in comparison to the normal CS Fe3O4@NiO (FN) MNPs. Both the CS systems have shown higher SAR values in comparison to the single-phased F owing to the EB coupling at the interface. However, the higher surface anisotropy of F shell with more EB field for NF enhanced the SAR value as compared to FN system. The EB coupling is hindered at higher concentrations of NF MNPs because of the enhanced dipolar interactions (agglomeration of nanoparticles). Both the CS systems reach to the hyperthermia temperature within 10 min. The cyto-compatibility analysis resulted in the excellent cell viability (> 75%) for 3 days in the presence of the synthesized NPs upto 1 mg/ml. These observations endorsed the suitability of CS nanoassemblies for magnetic fluid hyperthermia applications.

show abstract

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

Tsopoe

Borgohain

Fopase

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…At the interface of CoO/permalloy, the coercivity is enhanced by CoO defects, and the exchange bias is 7.5 Oe . With a good lattice matching, the exchange bias effect is greatly enhanced in Co/CoO Core/shell nanoparticles . Not only is at the interface with an AFM phase the exchange bias effect observed, but it is observed at the interface of a spin‐glass and an FM phase .…”

Section: Introductionmentioning

confidence: 99%

Emerging High Coercivity and Huge Exchange Bias Effect in Single Phased Mn₁₋_xRu_xCo₂O₄ Compounds

Chang

Tang

Lian

et al. 2019

Adv Elect Materials

View full text Add to dashboard Cite

The inhomogeneous cationic distribution is an important factor determining physical properties, but it has seldom been observed in bulk. In Mn1−x Rux Co2O4, high‐resolution transmission electron microscopy images illustrate segregated cationic distributions in ball milled x = 0.3, x = 0.5. It facilitates magnetic phase separations and exchange couplings. Ball milled x = 0.3 is antiferromagnetic accompanied with frustrated moments with exchange bias field 14.8 kOe. The coercivity of ball milled x = 0.1 is very high, 16.5 kOe. In x = 0.2, 0.4, and 0.5, both enhanced coercivities and exchange bias effects are observed. These phenomena are related to exchange couplings. In samples with solid state reaction, high coercivities are obtained in x = 0.3 as 16.3 kOe and in x = 0.2 as 4.4 kOe, while low coercivities are observed in x ≤ 0.1 and x = 0.5. After being annealed at high pressure and high temperature, homogeneous samples without ionic segregations display low coercivity of 30 Oe. In Mn1−x Rux Co2O4, both the coercivity increment and the bias field are higher than those reported in multilayer interfaces or core/shell nanoparticles. This is due to the perfect interfaces between different magnetic phases in one compound. A new strategy toward high‐performance permanent magnets with high coercivities is presented.

show abstract

“…In recent years, the synthesis of magnetic materials in the form of thin films and nanoparticles has been investigated for various applications due to their unique magnetic properties [ 1 , 2 , 3 ]. Magnetically soft films of Permalloy (Py) were the topic of special attention of researchers for many years, first of all, due to their wide use in micro- and nanoelectronics [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Structural and Magnetic Properties of Ni0.8Fe0.2/Ti Nanoscale Multilayers

et al. 2018

Self Cite

View full text Add to dashboard Cite

The influence of the thickness of the Ni0.8Fe0.2 (Permalloy, Py) layers on the structural and magnetic properties of magnetron sputtered Py/Ti multilayers was studied. The thickness of the Py layers was varied in the interval of 8 to 30 Å. X-ray reflectivity scans evidence the existence of a well-defined layered structure in all the samples considered, but also the presence of a complex intermixed interface. The shape of both the temperature dependence of magnetization and the hysteresis loops of the multilayered structures depends strongly on Py thickness. Magnetic and reflectivity measurements were comparatively analyzed in order to better understand the structure of the samples, and specifically, their interfaces. In particular, the presence of small superparamagnetic Py at the interfaces of the samples, especially evident in the samples with the thinnest Py layers, seems confirmed by the magnetic measurements, agreeing well with the reflectivity results.

show abstract

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

Cited by 40 publications

References 71 publications

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

Emerging High Coercivity and Huge Exchange Bias Effect in Single Phased Mn₁₋_xRu_xCo₂O₄ Compounds

Structural and Magnetic Properties of Ni0.8Fe0.2/Ti Nanoscale Multilayers

Contact Info

Product

Resources

About

Maximizing Exchange Bias in Co/CoO Core/Shell Nanoparticles by Lattice Matching between the Shell and the Embedding Matrix

Cited by 40 publications

References 71 publications

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

Emerging High Coercivity and Huge Exchange Bias Effect in Single Phased Mn1−xRuxCo2O4 Compounds

Structural and Magnetic Properties of Ni0.8Fe0.2/Ti Nanoscale Multilayers

Contact Info

Product

Resources

About

Emerging High Coercivity and Huge Exchange Bias Effect in Single Phased Mn₁₋_xRu_xCo₂O₄ Compounds