Temperature induced magnetization reversal in SrRuO3

Sarkar, Babusona; Dalal, Biswajit; De, S. K.

doi:10.1063/1.4850737

Cited by 16 publications

(7 citation statements)

References 23 publications

(21 reference statements)

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“…The temperature dependence of the magnetic susceptibility data of NL004, in the experimental mode of ZFC-FC with a very low external magnetic field (50 Oe), is also shown in Figure 2. The linear temperature dependence of the ZFC susceptibility data is related to the domain wall pinning processes [54] and the negative values at low temperatures are a direct consequence of the existence of magnetic interactions, possible crystal structure disorders and intrinsic negative spin polarization [55,56].…”

Section: Magnetic Propertiesmentioning

confidence: 99%

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Tangoulis

Lalioti

Parthenios

et al. 2020

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A new pH-sensitive system designed for drug-delivery purposes and based on functionalized multiwall magnetic carbon nanotubes (Mag-CNTs) was synthesized for the effective incorporation of non-steroidal anti-inflammatory drugs (NSAIDs), aiming at drug release in characteristic acidic conditions close to the actual conditions of inflamed tissues. Cationic hyperbranched polyethyleneimine (PEI) was immobilized on the surface of Mag-CNTs via electrostatic interactions between the positively charged protonated amines within the polymer and the carboxyl groups on the chemically oxidized Mag-CNT surface. The addition of the NSAID with a carboxylate donor, Naproxen (NAP), was achieved by indirect coupling through the amino groups of the intermediate linker PEI. FT-IR, Raman, and UV–vis spectroscopy were employed to fully characterize the synthesized nanocarrier and its functionalization procedure. The interaction of the designed nanocarrier with bovine serum albumin (BSA) was studied in vitro by fluorescence emission spectroscopy while its in vitro interaction with calf-thymus (CT) DNA was monitored by UV–vis spectroscopy and viscosity measurements and via competitive studies with ethidium bromide. The calculated binding constants were compared to those of free NAP revealing a higher binding affinity for BSA and CT DNA. Finally, drug-release studies were performed, revealing that the electrostatic linkage ensures an effective release of the drug in the acidic pH typical of inflamed cells, while maintaining the multiwall nanotubes (MWNTs)–drug conjugates stable at the typical bloodstream.

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Section: Magnetic Propertiesmentioning

confidence: 99%

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Tangoulis

Lalioti

Parthenios

et al. 2020

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“…The observation of giant MCE in Gd 5 Si 2 Ge 2 , due to simultaneous occurrence of structural and magnetic phase transitions near room temperature, stimulates researchers to enhance the activity in this field [40]. A number of magnetocaloric materials such as manganites [41][42][43][44], ruthenates [45,46], and Heusler alloys [47] has been investigated to find suitable materials for potential application. The MCE is defined as the change in magnetic entropy (∆S) with the variation of magnetic field.…”

Section: Magnetizationmentioning

confidence: 99%

Evolution of magnetic properties and exchange interactions in Ru doped YbCrO₃

Dalal

Sarkar

Ashok

et al. 2016

J. Phys.: Condens. Matter

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Magnetic properties of YbCr1-x Ru x O3 as a function of temperature and magnetic field have been investigated to explore the intriguing magnetic phenomena in rare-earth orthochromites. A quantitative analysis of x-ray photoelectron spectroscopy confirms the mixed valence state (Yb(3+) and Yb(2+)) of Yb ions for the highest doped sample. Field-cooled magnetization reveals a broad peak around 75 K and then becomes zero at about 20-24 K, due to the antiparallel coupling between Cr(3+) and Yb(3+) moments. An increase of the Ru(4+) ion concentration leads to a slight increase of compensation temperature T comp from 20 to 24 K, but the Néel temperature remains constant. A larger value of the magnetic moment of Yb ions gives rise to negative magnetization at low temperature. An external magnetic field significantly modifies the temperature dependent magnetization. Simulation of temperature dependent magnetization data, below T N, based on the three (two) magnetic sub-lattice model predicts stronger intra-sublattice exchange interaction than that of inter-sublattice. Thermal hysteresis and Arrot plots suggest first order magnetic phase transition. Random substitution of Ru(4+) ion reduces the magnetic relaxation time. Weak ferromagnetic component in canted antiferromagnetic system and negative internal magnetic field cause zero-field-cooled exchange bias effect. Large magnetocrystalline anisotropy associated with Ru creates high coercivity in the Ru doped sample. A maximum value of magnetocaloric effect is found around the antiferromagnetic ordering of Yb(3+) ions. Antiferromagnetic transition at about 120 K and temperature induced magnetization reversal lead to normal and inverse magnetocaloric effects in the same material.

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“…The negative values of the ZFC magnetization curve at low temperatures can be explained by a low applied magnetic field, lower than the coercivity of nickel nanoparticles, thus resisting alignment in the direction of the field due to their large magnetic anisotropy. Alternatively, the negative ZFC magnetization can be observed as a consequence of the presence of magnetic exchange interactions, random orientation of the easy axis, intrinsic negative spin polarization, or crystal structure disorders …”

Section: Resultsmentioning

confidence: 99%

Noncovalent Grafting of a Dy^III₂Single-Molecule Magnet onto Chemically Modified Multiwalled Carbon Nanotubes

et al. 2018

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While synthetic methods for the grafting of nanoparticles or photoactive molecules onto carbon nanotubes (CNTs) have been developed in the last years, a very limited number of reports have appeared on the grafting of single-molecule magnets (SMMs) onto CNTs. There are many potential causes, mainly focused on the fact that the attachment of molecules on surfaces remains not trivial and their magnetic properties are significantly affected upon attachment. Nevertheless, implementation of this particular type of hybrid material in demanding fields such as spintronic devices makes of utmost importance the investigation of new synthetic protocols for effective grafting. In this paper, we demonstrate a new experimental protocol for the noncovalent grafting of Dy SMM, [Dy(NO)(saph)(DMF)], where Hsaph = N-salicylidene- o-aminophenol and DMF = N, N-dimethylformamide, onto the surface of functionalized multiwalled CNTs (MWCNTs). We present a simple wet chemical method, followed by an extensive washing protocol, where the cross-referencing of data from high-resolution transmission electron microscopy combined with electron energy loss spectroscopy, conventional magnetic measurements (direct and alternating current), X-ray photoelectron spectroscopy, and Raman spectroscopy was used to investigate the physical properties, chemical nature, and overall magnetic behavior of the resulting hybrids. A key point to the whole synthesis involves the functionalization of MWCNTs with carboxylic groups, which proved to be a powerful strategy for enhancing the ability to process MWCNTs and facilitating the preparation of hybrid composites. While in the majority of analogous hybrid materials the raw carbon material (multiwalled or single-walled nanotubes) is heavily treated to minimize the contribution of contaminant traces of magnetic nanoparticles with important effects on their electronic properties, this method can lead easily to elimination of the largest part of the impurities and provide an effective way to investigate/discriminate the magnetic contribution of the SMM molecules.

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Temperature induced magnetization reversal in SrRuO3

Cited by 16 publications

References 23 publications

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Evolution of magnetic properties and exchange interactions in Ru doped YbCrO₃

Noncovalent Grafting of a Dy^III₂Single-Molecule Magnet onto Chemically Modified Multiwalled Carbon Nanotubes

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Temperature induced magnetization reversal in SrRuO3

Cited by 16 publications

References 23 publications

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Facile Method to Prepare pH-Sensitive PEI-Functionalized Carbon Nanotubes as Rationally Designed Vehicles for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery

Evolution of magnetic properties and exchange interactions in Ru doped YbCrO3

Noncovalent Grafting of a DyIII2Single-Molecule Magnet onto Chemically Modified Multiwalled Carbon Nanotubes

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Product

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Evolution of magnetic properties and exchange interactions in Ru doped YbCrO₃

Noncovalent Grafting of a Dy^III₂Single-Molecule Magnet onto Chemically Modified Multiwalled Carbon Nanotubes