R&D: Thermal Conductance Analysis of [FePt/h-BN/FePt] Interface

IEEE Transactions on Magnetics has published an article written by Chengchao Xu, Enbo Zhang, Bo-Yuan Yang, B.S.D.Ch.S. Varaprasad, Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA, USA, and Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA, David E. Laughlin, and Jian-Gang Zhu, Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA, USA, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA, and Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.

Abstract: “Heat-assisted magnetic recording (HAMR) requires a high thermal gradient in the recording media to suppress jitter noises. The FePt-(h-BN) granular film has been proposed as a promising media due to the formation of columnar grains in the film structure. It is also expected to have a low in-plane thermal conductivity for enhanced thermal gradient. Accurate measurements of the thermal conductance of nanometer-scale thin films remain challenging, but multilayer structure can provide an important platform to study the thermal transport in nanocomposite materials. Here we report on the fabrication and thermal characterization of [h-BN/L1 ₀ -FePt]× N multilayers, where h-BN nanosheets (2.5 nm thick) and Ll ₀ -FePt layers (6.5 nm thick) alternate periodically. Differential three-omega(3ω) measurements reveal an ultralow effective thermal conductivity of 0.60 ± 0.05W∙m ^-1 K ^-1 across the multilayer films, and a low thermal boundary conductance (TBC) of 67.9 ± 6.6 MW∙m ^-2 K ^-1 for the [FePt/h-BN(2.5nm)/FePt] interface at room temperature. The weak van der Waals bonding at the h-BN/FePt interface is considered the primary contributor to its high thermal resistance. This work can advance the understanding of thermal transport across the 2D-material/metal contacts and provide valuable insights for the design of HAMR media with thermally isolated FePt grains.“