Impact of carbon segregant on microstructure and magnetic properties of FePt-C nanogranular films on MgO (001) substrate

Tunable electron transport with intergranular separation in FePt-C nanogranular films

“…It has been reported that films with granular size less than 4 nm shows a complete disorder in L1 0 structure and for the size greater than 7 nm a complete order [2]. Since our films are having granular size above 6nm as observed from the TEM micrographs, L1 0 ordering should be present in our samples as reported [20]. Perpendicular magnetic anisotropy is the direct consequence of L1 0 ordering.…”

Origin of enhanced anisotropy in FePt-C granular films revealed by XMCD

“…Within the next few years, magnetic recording technology is expected to transition from Perpendicular Magnetic Recording (PMR) to energy assisted technologies, such as Heat-Assisted Magnetic Recording (HAMR) 1 . For these applications, the L1 0 phase of FePt offering a very high magnetocrystalline anisotropy of 7 MJ/m 3 is the material system of choice 2,3 . The high anisotropy allows for pushing the smallest thermally stable grain sizes down to (3 ∼ 4) nm, which corresponds to a storage density of several Tbits/in 2 .…”

“…facilitating laser induced heating of the FePt media above its Curie temperature. Magnetically isolated granular FePt films are typically sputter deposited alongside other constituents that preferentially form grain boundary phases or segregants [3][4][5][6][7] . These constituents include carbon, oxides, nitrides and carbides.…”

“…For instance, a core-shell type of microstructure with an FeO x shell surrounding an FePt grain has been observed in FePt-SiO 2 systems 8 . While it is well understood that segregants and dopants in the FePt system strongly influence the magnetic bit recording parameters [3][4][5][6][7] , little is known about their effect on spin and orbital moments, and demagnetization field contributions.…”

Effects of high magnetic field annealing on FePt nanoparticles with shape-anisotropy and element-distribution-anisotropy

“…[5][6][7] Otherwise, the as-synthesized FePt NP always shows a fcc disorder structure, and annealing is required to form an L1 0 orderly phase, which has great prospects in the eld of magnetic storage, permanent magnets and magnetic catalysis. [8][9][10][11][12][13] The typical shape-anisotropy, element-distribution-anisotropy, and the meaningful disorder-order transition of concave-cube fcc-FePt NPs offer us an opportunity to study the evolution of microstructure and property for the anisotropic NPs during annealing.…”