Pushing the limits of relaxation and modulated-bath AC calorimetry.

• Main Author: Song, Zhibo.
• Other Authors: School of Physical and Mathematical Sciences
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/53679
• Institution: Nanyang Technological University

The measurement of low temperature specific heat provides us a great amount of information on the lattice and electronic properties. Many different designs and techniques have developed so far to conduct the low temperature specific heat measurement. In this project, a new relaxation colorimeter is designed to operate at a temperature between 1.5K and 300K with magnetic field up to 16T. Then a modulated-bath AC calorimetry is incorporated with the relaxation calorimeter is a single setup for the purpose of measuring specific heat at a wider temperature spectrum and on smaller (micro-scale) sample scale. This design also has the advantage that the DC offset which plagues conventional AC calorimeter can be eliminated by superposing an AC plus DC current supply to the joule heater. The detailed design of this calorimeter is investigated and the full working principle is explained. The measuring process is modelling and simulating mainly using MATLAB and LabVIEW software. The simulation will be conducted using 3 milligram pure copper for the temperature range from 2K to 10K based on the modulated-bath AC method. Results of the simulation have shown a great reliability of the calorimeter that the error for specific heat measurement is less than 0.05% under the condition that the working frequency is carefully selected.