Thermal annealing effect on FeCoB soft underlayer for perpendicular magnetic recording

Abstract

We study the noise performance of amorphous FeCoB soft underlayers (SULs) with radial magnetic anisotropy. 200 nm thick FeCoB films are sputter deposited and optionally postannealed for 8 s at different annealing powers. The correlation of SUL read-back noise with the magnetic and structural properties is studied using spin stand testing, in-plane magneto-optical Kerr effect measurements, magnetic force microscopy, and x-ray diffraction. The effects of annealing to achieve low read-back noise are examined. It is found that as-prepared films show large dc noise associated with stripe domains due to stress-induced perpendicular anisotropy. Thermal annealing reduces the internal stress and the films become magnetically anisotropic in the radial direction. The SUL-induced dc noise drops to the electronic noise floor. dc noise is found to decrease with an increase in annealing power until the films start to crystallize.

Magnetic properties of FeSiB thin films displaying stripe domains

“…The respective in-plane hysteresis loops are constituted by two distinct magnetization phases: an in-plane component accounting for about half of the total magnetization, which quickly reverses at fields close to the coercive field, and a linear approach to saturation, due to the perpendicularly magnetized stripe domains, whose magnetization progressively rotates under the application of an in-plane magnetic field. This loop shape is often referred to as a ''transcritical loop'' [8]. The thickest sample (t ¼ 600 nm), although still characterized by the presence of an out-of-plane anisotropy, shows more irregular stripe domains, indicating a progressive return of the magnetization on the sample plane.…”

The Influence of Heat Treatment on Soft Magnetic Properties of the Fe60Co10Mo2Y8B20Alloy

“…Admixture of other elements allows to modify their properties and to adjust to the requirements of the electricity industry [69]. The properties of alloys is also inuenced by suitable heat treatment [10,11].…”

Thickness dependence of crystalline state in FeZrNbCuB thin films obtained by sputter deposition

“…More recently, these families of magnetic materials have gained the attention of the community of researchers working on thin films; in fact, their soft magnetic properties and high permeability make them interesting for a number of applications, including soft underlayers for perpendicular recording [11,12], free layers in spin valves and magnetic tunnel junctions [13,14], flux concentrators or shields [15]. However, amorphous and nanocrystalline thin films very seldom retain the excellent soft magnetic properties of bulk ingots, ribbons and microwires with similar composition [16][17][18].…”