Texture formation and epitaxy of thin metal films and oriented growth of nanoparticles (NPs) on single crystal supports are of general interest for improved physical and chemical properties especially of anisotropic materials. In the case of FePt, the main focus lies on its highly anisotropic magnetic behavior and its catalytic activity, both due to the chemically ordered face-centered tetragon...

Monodispersed FePt nanoparticles are synthesized by reduction of iron(II) acetylacetonate and platinum(II) acetylacetonate with 1,2-hexadecanediol as the reducing reagent in the polyol process. As-prepared FePt nanoparticles are chemically disordered with fcc phase. Transmission electron microscopy (TEM) images show a self-assembled particle array with an average particle size of 3 nm and a sta...

We perform first-principles calculations to predict the morphology of L10 ordered FePt nanoparticles grown on Mg(Ti)O substrates with relevance to application in heat-assisted magnetic recording (HAMR) media. We show how incorporation of Ti into MgO substrates reduces the FePt adhesion energy from −1.29 (pure MgO) to −2.35 J/m2 (pure TiO). This effect is due to the formation of strong Fe-Ti bon...

We report on the out-of-plane thermal conductivities of tetragonal L10 FePt (001) easy-axis and cubic A1 FePt thin films via time-domain thermoreflectance over a temperature range from 133 K to 500 K. The out-of-plane thermal conductivity of the chemically ordered L10 phase with alternating Fe and Pt layers is ~23% greater than the thermal conductivity of the disordered A1 phase at room tempera...

Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multic...

Modification of chemical order in epitaxial FePt binary alloy thin films deposited on MgO 100 substrates was induced and investigated in real time using x-ray rapid thermal annealing XRTA . This is possible because synchrotron undulator radiation has sufficient power density to induce significant structural modifications in thin films and its energy can be tuned to optimize absorption in the sa...

In this paper, we report on the production of Fe cluster/FePt matrix nanocomposite permanent magnets. Monodispersed Fe clusters with sizes below 10 nm were formed by gas aggregation techniques. These Fe clusters were imbedded in an FePt matrix by alternate deposition from two sources. Specimens with a range of Fe cluster phase content from 0 to 30 vol% were produced by controlling deposition ti...

The comprehensive study of C/FePt granular multilayers prepared by ion-beam sputtering at room temperature and subsequent annealing is reported. The as-deposited multilayers consist of carbon-encapsulated FePt nanoparticles (average size ∼3 nm) with a disordered face-centered-cubic structure. The effects of thermal annealing on the structural and magnetic properties are investigated by using de...

The solid state reactions and structural evolution in nanocrystalline FePt powders during mechanical ball milling at 77 K and subsequent annealing have been investigated. Above 310 °C the formation of L10 FePt is observed. As the milling time increases, the enthalpy evolved during the transformations is reduced, whereas the corresponding activation energy increases. For accelerating the orderin...