Pump-probe thermoreflectance measurements of critical interfaces for thermal management of HAMR heads

MRS Advances ◽  
2017 ◽  
Vol 2 (58-59) ◽  
pp. 3627-3636
Author(s):  
Gregory T. Hohensee ◽  
Mousumi M. Biswas ◽  
Ella Pek ◽  
Chris Lee ◽  
Min Zheng ◽  
...  
Keyword(s):  
Thermal Management ◽  
Operating Temperature ◽  
Near Field ◽  
Thermal Conductance ◽  
Heat Sinks ◽  
Pump Probe ◽  
Thermal Boundary Conductance ◽  
Metal Metal ◽  
Metal Interfaces ◽  
Heat Sinking

ABSTRACT For heat-assisted magnetic recording (HAMR) heads, a major reliability limiter is the peak near-field transducer (NFT) temperature. Since the NFT is nanoscale, heat sinking is controlled by materials and interfaces within a few 100 nm of the NFT. Heat sinks can be metallic to take advantage of the 10x-100x higher thermal boundary conductance (TBC) of metal/metal interfaces, versus nonmetal interfaces. Oxide formation at these interfaces can greatly decrease the TBC and contribute to NFT failure. Likewise, the thermal resistance of material between the NFT and media recording layer greatly influences the NFT operating temperature. Here we use pump-probe thermoreflectance techniques (FDTR, TDTR) to study metal-metal interfaces and detect partial oxidation of a buried metallic thin film, as well as evaluate the interface thermal conductance of amorphous-amorphous interfaces in a film stack representative of a HAMR head-media interface.

Thermal conductance of metal-metal interfaces

2005 ◽  
Vol 72 (24) ◽  
Author(s):  
Bryan C. Gundrum ◽  
David G. Cahill ◽  
Robert S. Averback
Keyword(s):  
Thermal Conductance ◽  
Metal Metal ◽  
Metal Interfaces

Effects of subconduction band excitations on thermal conductance at metal-metal interfaces

2010 ◽  
Vol 96 (1) ◽  
pp. 011907 ◽  
Author(s):  
Patrick E. Hopkins ◽  
Thomas E. Beechem ◽  
John C. Duda ◽  
Justin L. Smoyer ◽  
Pamela M. Norris
Keyword(s):  
Thermal Conductance ◽  
Metal Metal ◽  
Metal Interfaces

Application Conditions of Effective Medium Theory in Near-Field Radiative Heat Transfer Between Multilayered Metamaterials

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
X. L. Liu ◽  
T. J. Bright ◽  
Z. M. Zhang
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Effective Medium Theory ◽  
Near Field ◽  
Effective Medium ◽  
Medium Theory ◽  
Metal Metal ◽  
Doped Silicon ◽  
Silicon And Germanium

This work addresses the validity of the local effective medium theory (EMT) in predicting the near-field radiative heat transfer between multilayered metamaterials, separated by a vacuum gap. Doped silicon and germanium are used to form the metallodielectric superlattice. Different configurations are considered by setting the layers adjacent to the vacuum spacer as metal–metal (MM), metal–dielectric (MD), or dielectric–dielectric (DD) (where M refers to metallic doped silicon and D refers to dielectric germanium). The calculation is based on fluctuational electrodynamics using the Green's function formulation. The cutoff wave vectors for surface plasmon polaritons (SPPs) and hyperbolic modes are evaluated. Combining the Bloch theory with the cutoff wave vector, the application condition of EMT in predicting near-field radiative heat transfer is presented quantitatively and is verified by exact calculations based on the multilayer formulation.

Influence of Interfacial Mixing on Thermal Boundary Conductance Across a Chromium/Silicon Interface

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Patrick E. Hopkins ◽  
Pamela M. Norris ◽  
Robert J. Stevens ◽  
Thomas E. Beechem ◽  
Samuel Graham
Keyword(s):  
Electron Spectroscopy ◽  
Finite Thickness ◽  
Thermal Conductance ◽  
Phase Region ◽  
Two Phase ◽  
Thermal Boundary Conductance ◽  
Si Substrates ◽  
Interfacial Mixing ◽  
Silicon Interface ◽  
Deposition Conditions

The thermal conductance at solid-solid interfaces is becoming increasingly important in thermal considerations dealing with devices on nanometer length scales. Specifically, interdiffusion or mixing around the interface, which is generally ignored, must be taken into account when the characteristic lengths of the devices are on the order of the thickness of this mixing region. To study the effect of this interfacial mixing on thermal conductance, a series of Cr films is grown on Si substrates subject to various deposition conditions to control the growth around the Cr∕Si boundary. The Cr∕Si interfaces are characterized with Auger electron spectroscopy. The thermal boundary conductance (hBD) is measured with the transient thermoreflectance technique. Values of hBD are found to vary with both the thickness of the mixing region and the rate of compositional change in the mixing region. The effects of the varying mixing regions in each sample on hBD are discussed, and the results are compared to the diffuse mismatch model (DMM) and the virtual crystal DMM (VCDMM), which takes into account the effects of a two-phase region of finite thickness around the interface on hBD. An excellent agreement is shown between the measured hBD and that predicted by the VCDMM for a change in thickness of the two-phase region around the interface.

Characterization of Light Weight Heat Sink Materials for Thermal Management of Electronics

2007 ◽  
Author(s):  
Tunc Icoz ◽  
Mehmet Arik ◽  
John T. Dardis
Keyword(s):  
Thermal Management ◽  
Heat Sink ◽  
High Efficiency ◽  
Computational Study ◽  
Heat Sinks ◽  
Advanced Materials ◽  
Air Cooling ◽  
Thermal Management Of Electronics ◽  
Thermal Solution

Thermal management of electronics is a critical part of maintaining high efficiency and reliability. Adequate cooling must be balanced with weight and volumetric requirements, especially for passive air-cooling solutions in electronics applications where space and weight are at a premium. It should be noted that there are systems where thermal solution takes more than 95% of the total weight of the system. Therefore, it is necessary to investigate and utilize advanced materials to design low weight and compact systems. Many of the advanced materials have anisotropic thermal properties and their performances depend strongly on taking advantage of superior properties in the desired directions. Therefore, control of thermal conductivity plays an important role in utilization of such materials for cooling applications. Because of the complexity introduced by anisotropic properties, thermal performances of advanced materials are yet to be fully understood. Present study is an experimental and computational study on characterization of thermal performances of advanced materials for heat sink applications. Numerical simulations and experiments are performed to characterize thermal performances of four different materials. An estimated weight savings in excess of 75% with lightweight materials are observed compared to the traditionally used heat sinks.

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