High frequency alternating current chip nano calorimeter with laser heating

Journal Article · Mon Jul 15 00:00:00 EDT 2013 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4812349· OSTI ID:22220558

Shoifet, E.; Schick, C. ^[1]; Chua, Y. Z.; Huth, H. ^[1]

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1. Institute of Physics, University of Rostock, Wismarsche Str. 43-45, 18051 Rostock (Germany)

Heat capacity spectroscopy at frequencies up to 100 kHz is commonly performed by thermal effusivity measurements applying the 3ω-technique. Here we show that AC-calorimetry using a thin film chip sensor allows for the measurement of frequency dependent heat capacity in the thin film limit up to about 1 MHz. Using films thinner than the thermal length of the thermal wave (∼1 μm) at such frequencies is advantageous because it provides heat capacity alone and not in combination with other quantities like thermal conductivity, at least on a qualitative basis. The used calorimetric sensor and the sample are each less than 1 μm thick. For high frequency AC-calorimetry, high cooling rates at very small temperature differences are required. This is realized by minimizing the heated spot to the size of the on chip thermocouple (3 × 6 μm{sup 2}). A modulated laser beam shaped and positioned by a glass fiber is used as the heat source. The device was used to measure the complex heat capacity in the vicinity of the dynamic glass transition (structural relaxation) of poly(methyl methacrylate). Combining different calorimeters finally provides data between 10{sup −3} Hz and 10{sup 6} Hz. In this frequency range the dynamic glass transition shifts about 120 K.

• OSTI ID: 22220558
• Journal Information: Review of Scientific Instruments, Vol. 84, Issue 7; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALTERNATING CURRENT
BEAMS
CALORIMETERS
CALORIMETRY
ELECTRIC HEATING
FREQUENCY DEPENDENCE
FREQUENCY MEASUREMENT
KHZ RANGE
LASER-RADIATION HEATING
LASERS
METHACRYLIC ACID ESTERS
MHZ RANGE
SENSORS
SPECIFIC HEAT
THERMAL CONDUCTIVITY
THERMOCOUPLES
THIN FILMS