The data in this folder are from this publication:

2007	Hofmeister, A.M. Thermal diffusivity of aluminous spinels and magnetite at elevated temperature 
with implications for heat transport in Earth’s transition zone. American Mineralogist 92, 1899-1911

Keywords: Laser-flash method, high temperature, thermal diffusivity, IR spectroscopy, spinel-
family minerals, high pressure, aluminates

Data collected at Washington University, St. Louis, MO.  The tables represent all thermal data collected.  

I thank M. Pertermann and G. Benedix for obtaining electron microprobe
analyses. this publication was supported by nSF grant eaR-0207198.

Tables from the ms are in excell. The contents are:

Table 1. Sample characteristics and electron microprobe analyses

Table 2. Run conditions and fits to thermal diffusivity at temperature

Table 3. Compositional trends for mainly Fe substitution

theother Excel files are older cryogenic data: caveat emptor.

The xxxx.prn files are ascii files of the spectral data of the samples listed in table 1. These are not baseline corrected; 
Format is the left column is in wavenumbers and the right column is in absorbance units (base 10).  Some unpublished data is included. 


Abstract:
The phonon component of thermal diffusivity (D) from 12 single crystals in the spinel family was
measured at temperatures (T) of up to ~2000 K, using laser-flash analysis. Synthetic disordered spinel,
4 gemstones near MgAl2O4, nearly ZnAl2O4, 4 “hercynites” [(Mg,Fe2+)(Al,Fe3+)2O4], and 2 magnetites
(nearly Fe3O4) were characterized using optical spectroscopy and electron microprobe analysis. The
magnetic transition in Fe3O4 is manifest as a lambda curve in 1/D, but otherwise, D decreases with
increasing T and approaches a constant (Dsat) at high T. Part of the decrease in D as T increases results
from disordering above ~700 K: these two effects were distinguished by making multiple heating runs.
At 298 K, D decreases strongly as either cation substitution or Mg-Al disorder increases, whereas Dsat
is moderately perturbed by substitutions. For both ordered and (equilibrium) disordered spinels and
hercynites, the temperature dependence of 1/D is best described by low-order polynomial fits. For
spinel, combining our data with previous cryogenic studies of thermal conductivity (k) constrains the
T dependence of D and k from ~0 K to melting.
The response of D to disorder, impurity content, and cation mass for the aluminates is used to
constrain D(T) for γ-Mg2SiO4 and ringwoodite. Pressure derivatives are provided by relationships
such as ∂ln(klat)/∂P = ∂ln(KT)/∂P. Our results show that the phonon contribution to heat transport in
Earth’s transition zone is high, particularly for large proportions of ringwoodite