Thermal transport properties of single crystal lanthanum aluminate

Abstract

The thermal diffusivity and thermal conductivity of single crystal (100) lanthanum aluminate (LaAlO3) have been determined in the temperature range 77–353 K. The thermal diffusivity was measured using a transient heat-pulse technique and the thermal conductivity by a steady state dc technique. The specific heat capacity was calculated from the thermal diffusivity and thermal conductivity data obtained. The temperature dependence of the thermal diffusivity was found to be of the form [T exp(TD/bdT)] and that of the thermal conductivity of the form [T3 exp(TD/bcT)]. Both results are consistent with the expected behavior of the thermal transport, limited by phonon-phonon collision (‘‘Umklapp’’) processes, in high purity dielectric single crystals. The Debye temperature (TD) was calculated as 720±22 K and the parameters bd and bc were found to be 1.4±0.1 and 0.7±0.1, respectively. The average sound velocity was calculated to be (5.4±0.6)×105 cm/s. The phonon mean-free-path at 303 K was found to be (2.2±0.2)×10−7 cm.

Demonstration of a picosecond Bragg switch for hard X-rays in a synchrotron-based pump–probe experiment

“…Having determined the sample geometry by static XRD and ellipsometry measurements, we adjust the simulated dynamics via the sound velocity in LSMO and LAO, respectively, to the experimental data. The result agrees well with values reported by other groups 35,36 . For comparison, a similar experiment reported earlier by our group gave 20% higher sound velocities due to insufficient temporal and angular resolution of our XRD setup 18 .…”

Time spectroscopy of a film bolometric response to mm-waves power as a method of the thermodynamic coefficients diagnostics in a film structures

“…=1.38ms. The value of coefficients of both specific heat capacity (c, =152.2J/kg K) and thermal conductivity (h, =17.47W/m K) of a lanthanum aluminate were obtained in good agreement with a other method data [4].…”

“…Second idealized process (curve 2 of fig.2b) is corresponded to zero thermal conductivity of substratethermostat interface. The temperature of the substrate boundary near the film-substrate interface (x=O) is described by equation (4) [2], where AT2 = P, D/(3SLs) and z2= c,psD'/ hSt. 00 T,(t)= Pj t /(csps v,) + AT2 ( 1 -(6/7c2) (l/n2) exp(-n2n2t/z 2)).…”

“…00 T,(t)= Pj t /(csps v,) + AT2 ( 1 -(6/7c2) (l/n2) exp(-n2n2t/z 2)). (4) Curves (3) and (4) where AT, =Pj /S A,, =P, kt and 73 = kt (cf pf vf fc, psv, ). As it's seen fiom fig.2b and f i g .…”

Complete thermal characterization of film-on-substrate system by modulated thermoreflectance microscopy and multiparameter fitting

“…Both values are very close to the literature value. 14 Regarding the measurement of the substrate diffusivity, Fig. 2 evidences that a low-diffusivity film is advantageous: curve 2-D s is narrower than curve 1-D s .…”