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To increase the storage capacity of hard disk drives, Heat-Assisted Magnetic Recording (HAMR) takes advantage of laser heating to temporarily reduce the coercivity of recording media, enabling the writing of very small data bits on materials with high thermal stability. One key challenge in implementing HAMR is effective thermal management, which requires reliable determination of the thermal properties of HAMR materials over their range of operating temperature. This work reports the thermal properties of dielectric (amorphous silica, amorphous alumina, and AlN), metallic (gold and copper), and magnetic alloy (NiFe and CoFe) thin films used in HAMR heads from room temperature to 500 K measured with time-domain thermoreflectance. Our results show that the thermal conductivities of amorphous silica and alumina films increase with temperature, following the typical trends for amorphous materials. The polycrystalline AlN film exhibits weak thermal anisotropy, and its in-plane and through-plane thermal conductivities decrease with temperature. The measured thermal conductivities of AlN are significantly lower than that which would be present in single-crystal bulk material, and this is attributed to enhanced phonon-boundary scattering and phonon-defect scattering. The gold, copper, NiFe, and CoFe films show little temperature dependence in their thermal conductivities over the same temperature range. The measured thermal conductivities of gold and copper films are explained by the diffuse electron-boundary scattering using an empirical model. 

Abstract Concept screening is one of the gatekeepers of innovation process and thus is considered a vital component of engineering design. Yet, we know very little about how decisions are made during concept screening or the factors that inform these decisions. This is due, in part, to the fact that most prior work on concept screening in engineering design has focused on student populations or on industry professionals in an experimental setting which is not indicative of the risks and consequences professionals face in their daily work—particularly when it comes to innovative design process. Thus, the current study was developed to identify how the environmental settings (i.e., experimental versus naturalistic) and the role of the professionals in the design process (i.e., idea generators versus executives) impacts the criteria used to screen design ideas. Two studies were conducted including a workshop study with 45 design professionals from two companies in an experimental setting and a participatory ethnographic study with seven design professionals from a small electromechanical company in a naturalistic setting. The results showed stark differences in the criteria used to screen ideas between naturalistic and experimental practices and between idea generators and company executives. In addition, the results showed differences in the factors considered during concept screening between naturalistic and experimental environments. These results are used to identify opportunities for tools and methods that encourage the consideration of creative ideas in the engineering design industry and encourage appropriate risk-taking in engineering design.