Quantifiable combinatorial materials science approach applied to perpendicular magnetic recording media

Abstract

Deposition of films with controlled gradients across the wafer in terms of both composition and thickness were used together with statistical experimental design methodologies to explore large parameter spaces relevant to the optimization of perpendicular magnetic recording media. With this approach, thickness and composition of the media and the interdependencies of these variables were efficiently investigated and correlated to the coercivity of the material and the squareness of the hysteresis loops. To determine dependencies and codependencies between additives to CoCr alloys on the magnetic properties, this method was used to study magnetic layers of CoCrPt, CoCrPtTa, CoCrPtTi, and CoCrTiTa. The best models associated with each alloy had the same terms for the three magnetic parameters measured (Hc, S, and θk,perp). Additions to the CoCr alloy introduced dependencies on the Cr and cross-term dependencies with Cr (i.e., CrTa, CrPt, or CrTi). In some cases, thickness became an important parameter and for the CoCrPtTa case, the Pt concentration directly influenced the magnetic properties. These findings, obtained in a concise manner with fully descriptive empirical models, agree with the bulk of published literature. In this study, the variables are tightly controlled and variables such as temperature and residual gas concentrations are identical for all data points used within each alloy system generating an accurate transfer function. Once the transfer function between the input and output parameters is established, the sensitivity or stability to changes in the different factors can easily be investigated.

Electrochemical Corrosion Investigation of 49-Cell Combinatorial Library of Titanium-Based Alloys Fabricated by DMD

“…The sample size and geometry must therefore be designed to match the requirement of the appropriate screening method. [7][8][9][10] A previous study 11 demonstrated electrochemical corrosion screening of a 7-cell library of titanium alloys fabricated using direct metal deposition ͑DMD͒. This article extends that work and reports the fabrication and efficient screening for 49-cell libraries.…”

Applications of combinatorial approach to the investigation of optical functional materials

“…In the search for novel MO storage materials, the Kerr rotation angle is an important parameter since higher Kerr rotation leads to a better signal-to-noise ratio. Tsui et al [7][8][9] adopted the combinatorial methodology in the research on novel MO materials. However, the lack of proper characterization tools limited the efficiency gain.…”

“…Fortunately, characterization of the optical properties is natural parallel, i.e., either excitation/emission or irradiation/reflection is easy to achieve high spatial resolution under parallel analysis. So, applications of combinatorial method to the investigation of functional optical materials such as luminescent, electro-optical, magneto-optical materials have been carried out extensively [3][4][5][6][7][8][9][10][11] . Below, the progress in this area will be introduced by using the recent studies conducted by the authors as samples.…”

Current Status of Combinatorial and High‐Throughput Methods for Discovering New Materials and Catalysts

“…Among metal alloys, the Ni À Mn À Ga system [83] and Co Cr alloy with small amount of additives were fabricated using a co-sputtering system [84]. In addition, Ni 1-x Fe x library was deposited by pulsedlaser deposition (apparatus equipped with an automated shutter) [85].…”

“…However, to measure the hysteresis loop that is the important feature of ferromagnetism, a magneto-optical Kerr-effect (MOKE) instrument has been used. The parameters, including coercivity, squareness, and maximum angular perpendicular Kerr rotation were derived from these loops and used for fitting data for calculation of coercivity and squreness by input of the composition and thickness [84,97].…”