Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature.

Study on magnetic properties of a nano-graphene bilayer

Electrical transport and magnetoresistance in advanced polyaniline nanostructures and nanocomposites

Synthesis of Wafer-Scale Graphene with Chemical Vapor Deposition for Electronic Device Applications

In this work, an ultrasensitive and ultraselective chemiluminescence (CL) aptasensor was prepared for dopamine (DA) detection based on aptamers modified magnetic mesoporous silica @ graphite oxide polymers (Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO). Firstly, Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO and Au nanoparticles (AuNPs) were prepared and characterizated by transmission electron microscopy (TEM), scanning electron microscope (SEM), fourier transform infrared (FTIR), X-ray powder diffraction (XRD) and others. Then, dopamine aptamer (D-Apt) was immobilized on the surface of Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO while AuNPs was modified by ssDNA (a single stranded DNA partially complementary to D-Apt). The immobilization properties of Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO to D-Apt and the adsorption properties of Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO@D-Apt to AuNPs@ssDNA were researched sequentially. When DA existed, AuNPs@ssDNA was desorbed from the surface of Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO@D-Atp and catalyzed luminescence. After that, under optimized CL conditions, DA could be measured with the linear concentration range of 2.5 × 10 −13 to 2.0 × 10 −9  mol/L. The detection limit was 3.9 × 10 −14  mol/L (3δ) while the relative standard deviation (RSD) was 2.6%. Finally, the Fe 3 O 4 ·mSiO 2 ·nSiO 2 @GO@D-Apt/AuNPs@ssDNA − CL aptasensor was used for the determination of DA in practical samples and recoveries ranged from 98.0% to 102.0%. Those satisfactory results clarified the proposed CL aptasensor achieved ultraselective, ultrasensitive and reliable detection of DA and revealed potential application in monitoring and diagnosis of human neurological diseases.

An ultrasensitive and ultraselective chemiluminescence aptasensor for dopamine detection based on aptamers modified magnetic mesoporous silica @ graphite oxide polymers

Room Temperature Magnetic Graphene Oxide‐ Iron Oxide Nanocomposite Based Magnetoresistive Random Access Memory Devices via Spin‐Dependent Trapping of Electrons

Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A.m$^2$/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite.

/pdf/tunable-room-temperature-ferromagnet-using-an-iron-oxide-and-3aqlv9475v.pdf

Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite

Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation is manipulated for functionality. Here we demonstrate an iron-oxide and graphene oxide nanocomposite based device that acts as a tunable ferromagnet at room temperature. Not only can we tune its transition temperature in a wide range of temperatures around room temperature, but the magnetization can also be tuned from zero to 0.011 A m2/kg through an initialization process with two readily accessible knobs (magnetic field and electric current), after which the system retains its magnetic properties semi-permanently until the next initialization process. We construct a theoretical model to illustrate that this tunability originates from an indirect exchange interaction mediated by spin-imbalanced electrons inside the nanocomposite.

Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite.

We demonstrate a polyaniline-iron oxide nanoparticle (PANI-NP) organic hybrid composite device with room temperature positive magnetoresistance of 85.7%. Temperature dependent resistivity measurements attribute this observation to the decrease in localization length of the charge carriers in the presence of an external magnetic field which result in them being trapped within the device between the insulating PANI layer, hence allowing the device to maintain its resistive state even when the power is switched off, thus exhibiting a memory effect.

/pdf/room-temperature-positive-magnetoresistance-via-charge-4z8wiltm50.pdf

Aigu L. Lin

Papers

Room Temperature Magnetic Graphene Oxide‐ Iron Oxide Nanocomposite Based Magnetoresistive Random Access Memory Devices via Spin‐Dependent Trapping of Electrons

Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite

Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocomposite.

Room temperature positive magnetoresistance via charge trapping in polyaniline-iron oxide nanoparticle composites