Additive Effects of AlN and MgO on FePt Nanoparticle Assembly

Abstract

We have studied the additive effects of AlN and MgO on L1 0 -FePt nanoparticles by co-sputtering FePt and AlN (or MgO) on MgO(100) substrates at 973 K. Good epitaxial growth of FePt was confirmed both for AlN and MgO. With the increase of the additive content, the long range order (LRO) of L1 0 phase appeared to increase for AlN, whereas it was suppressed for MgO. Morphological observation by addition of AlN, well-isolated FePt particles became to connect each other, and finally formed a maze-like structure. On the other hand, the morphology of FePt particles was hardly affected by addition of MgO.

Epitaxially grown L10-FePt/(C, SiO2, and Al2O3) granular films

“…On the other hand, (I 0 0 1 /I 0 0 2 ) 0.5 gradually decreases up to 40 vol% and then drops to zero at 51 vol%. These behaviors seem to be analogous to that for MgO additive [2], although the physical mechanism for these behaviors is still unclear.…”

“…Although epitaxially grown L1 0 -FePt nanoparticles exhibited excellent c-axis orientation [1], its size distribution was rather broad due to the coalescence of adjacent particles during film growth. Therefore, to suppress the coalescence, AlN and MgO were added to the epitaxially grown L1 0 -FePt particulate films [2]. These additives effectively reduce the FePt particle size while keeping the epitaxial growth of FePt.…”

Microstructure and magnetic properties of FePt-SiO2 granular films with Ag addition

“…Many investigations on the fabrication of the FePt granular films by the sputtering technique have been made. [22][23][24][25][26][27][28] However, controlling the particle size is difficult since most of the granular films are deposited at room temperature, and a postannealing becomes necessary for the L1 0 ordering. Okamoto et al fabricated FePt-AlN and FePt-MgO granular films on heated MgO substrates; 22 however, the average particle size was too large to be considered for the high-density recording media.…”

“…[22][23][24][25][26][27][28] However, controlling the particle size is difficult since most of the granular films are deposited at room temperature, and a postannealing becomes necessary for the L1 0 ordering. Okamoto et al fabricated FePt-AlN and FePt-MgO granular films on heated MgO substrates; 22 however, the average particle size was too large to be considered for the high-density recording media. To obtain highly ordered FePt nanogranular film with a narrow size distribution, we prepared FePt-SiO 2 granular films at various substrate temperatures and investigated the relationship between the microstructure and magnetic properties.…”