Interface Mediated Thermal Transport: From Hybrid Materials to Hard Disk Drives

Jonathan A. Malen, Carnegie Mellon University

January 13, 11:00 - 12:00pm, EBUII 479 von Karman-Penner Seminar Room

Abstract:  Operating temperature, and hence heat dissipation, impact the performance of energy conversion technologies and electronic devices.  Thermal transport in advanced materials for these technologies cannot be described simply by Fourier’s law when the mean free paths of energy carriers are commensurate to feature sizes. Instead, interfaces and non-diffusive transport can govern macroscopic quantities like thermal conductivity.  The objective of my research group is to experimentally measure these effects, to better design and understand these materials. I will begin with an introduction to the nanoscale heat carriers, and I will then present two projects where interfaces influence performance.  (1) Nanocrystal arrays (NCAs) are self assembled organic-inorganic hybrid materials with novel electronic and optical properties.  Our measurements reveal that thermal transport in NCAs is mediated by surface chemistry defined interfaces between neighboring nanocrystals. Complementary measurements of self assembled monolayers (SAMs) shed light on phonon transport at the organic-inorganic interface.  (2) Heat assisted magnetic recording (HAMR) is a new data storage technology that exemplifies the need to minimize thermal interface resistance in concert with optimizing other interface functions.  In the case of HAMR, the unique plasmonic properties of Au-dielectric interfaces are critical to operation, and metals with inherently lower thermal interface resistance are unsuitable. To remedy this, we are studying tradeoffs in thermal and plasmonic performance of Au-dielectric interfaces enhanced by adhesion layers or through alloying with other metals.

Bio:  Jon recieved his Ph.D in Mechanical Engineering at the University of California, Berkeley under the co-advisory of Professors Arun Majumdar (ME, MSE) and Rachel Segalman (ChemE).  He investigated thermoelectricity in single molecule junctions, in an effort to learn more about electronic transport in molecular electronics and organic-inorganic hybrid materials.  Jon received his B.S. in Mechanical Engineering at the University of Michigan, Ann Arbor in 2000 and an S.M. in Nuclear Engineering (2003) from MIT, where he studied transport at the macroscopic reactor scale under the advisory of Professor Neil Todreas.  He spent one year as an intern at the Lawrence Livermore National Laboratory from 2003-2004, and was an NDSEG Fellow from 2005-2008.  Since his arrival at Carnegie Mellon in 2009, Jon has received the AFOSR Young Investigator Award (2011), ARO Young Investigator Award (2014), ACS PRF Doctoral New Investigator Award (2011), NSF CAREER Award (2012), and ASME Bergles-Rohsenhow Young Investigator Award in Heat Transfer (2014).