Influence of MgO underlayers on the structure and magnetic properties of FePt-C nanogranular films for heat-assisted magnetic recording media

Abstract

In order to optimize the nanogranular structure of FePt-C for heat-assisted magnetic recording media, we investigated the influence of MgO underlayers on the growth of FePt grains in the FePt-C layer. The FePt-C layer was deposited by using the alternating sputtering method, by which FePt and FePt-C layers were alternately deposited. To understand the growth mechanism of the FePt-C layer on the MgO underlayers deposited under various conditions, detailed plan-view and cross sectional transmission electron microscopy observations were made for different film thicknesses. We found that columnar FePt grains grow only when the deposition conditions of the MgO underlayer are optimal. Direct TEM observation of the growth process of the FePt-C layer revealed that the number density of nuclei is sufficient in the initial stage of the film deposition; however, coarsening of the grains after grain impingement causes a substantial decrease in the number density of the FePt grains.

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

“…Resistance and magnetoresistance in FePt-Ag multilayer films have been reported [19], in which a dip in resistance was observed at very low temperatures (<11 K). Carbon is an excellent segregant for FePt granular films, as it retains higher coercivity and smaller grain size distribution of FePt compared to other insulators such as B, SiO 2 , TiO 2 , etc., and also enhance L1 0 ordering [8]. Hence, in this paper, the effect of intergranular separation on resistivity of FePt-C granular films is presented.…”

“…Critical grain size of FePt granular films for superparamagnetism at room temperature is as low as 3 nm and L1 0 ordering of granules was observed for a granular size of above 7 nm [2]. A large number of studies are available in literature on these systems, observing its potential in magnetic recording media [3][4][5][6], varying the matrix material [7,8], annealing temperature [9] and substrates to avoid the diffusion of the matrix material and to raise the columnar growth of FePt. Recently, Electric field induced spin control in the perpendicular magnetic anisotropy films [10][11][12][13][14] has become an intriguing technique in spintronic devices, as it consumes ultra-low power and avoids joule heating occurring in current induced spin control.…”

Optical and thermal analysis of the light-heat conversion process employing an antenna-based hybrid plasmonic waveguide for HAMR

“…We use media like that previously published on HAMR devices although optimization of the media itself or write pole was not part of this study [5,[38][39][40][41][42][43][44]. Additionally, the distance between the write pole and heated spot within the recording layer is limited so that the applied external magnetic field effectively adjusts the magnetization in the recording layer.…”

CoPt–Al2O3 Nanocomposite Films: Synthesis, Structure, and Magnetic Properties

“…Тонкие пленки FePd, FePt и CoPt, упорядоченные по типу L1 0 , обладают большой константой магнитной анизотропии K 1 (K 1 > 3 × 10 7 эрг/см 3 ) с осью легкого намагничивания, расположенной перпендикулярно поверхности пленки (так называемая перпендикулярная магнитная анизотропия). Нанокомпозитные пленки, которые содержат изолированные высококоэрцитивные L1 0 -кластеры, вложенные в немагнитную матрицу [18][19][20][21][22][23][24][25], могут быть использованы для магнитной записи информации с высокой плотностью.…”