Laboratory, optical and precision equipments (excl. glasses)

Tender description

The University of Birmingham invites tenders for supply of a system for measuring physical properties with the following specifications: Temperature Control. a) Sample temperatures with a minimum range of 2 K to 400 K over the full magnetic field range and for all measurement options. A broader temperature range, particularly to lower temperatures would be welcome. b) Better than ± 1 % temperature accuracy across full field and temperature range. c) Better than ± 0.2 % stability for temperatures below 10 K. d) Bore size larger than or equal to 2.5 cm. e) A ‘no overshoot’ control method should be available. f) It should be possible to take measurements while sweeping the temperature and while stepping the temperature. For sweeping, the possible user-defined temperature rates shall be stated in the tender. g) Cryostat nature: If a wet cryostat is proposed, there should be both helium and nitrogen jackets, and a suitable helium transfer siphon should be included. The system autonomy and daily consumption rates with and without field change shall be stated in the tender. If a CCR option is proposed, the electrical power requirements, the cooldown time of the system from room temperature, and the maximum vibration levels of the magnet shall be stated in the tender. Field Control. a) A longitudinal magnetic field of not less than 9 T shall be provided, capable of operation in persistent and non-persistent modes. The decay rate in persistent mode shall be stated in the tender. b) Field uniformity of not less than 0.1 % over a cylindrical volume of height 5.5 cm and diameter 1 cm. c) Field resolution of 0.2 mT over the full field range. d) The field control method will permit oscillation of the field value while cooling the sample. e) The power supply should be bipolar, such that measurements may be carried out smoothly on going through 0 T. f) The maximum sweep rates of field shall be specified: faster rates will be preferred. Sample Rotation. a) Sample rotation over at least 360 degrees about an axis perpendicular to the field. b) Thermometry close to the sample on the part that rotates. c) Rotation step size and accuracy to be specified in the tender. Magnetic Measurements. a) AC susceptibility and DC magnetization measurements to be possible. b) AC frequency range to be specified; evaluation on range available. c) AC field amplitude range to be at least 5 mOe to 15 Oe. d) Sensitivity in DC measurements to be better than 3 x 10-5 emu over an averaging time of 10s. e) Sensitivity in AC measurements to be better than 2 x 10-8 emu at the highest frequency. Heat Capacity Measurements. a) A resolution of at least 10 nJ/K at 2 K should be provided. b ) Any processing that may be done to the data shall be noted in the tender; priority will be given to methods that reduce the work required to provide publishable data. c) Evaluation on the time taken to acquire each data point. Electrical Transport Measurements. a) DC resistivity measurements using a 4-point measurement technique. b) AC resistivity measurements. c) Hall effect measurement. d) Current-voltage characteristics. e) Current range, voltage sensitivity and frequency range to be specified in the tender. f) Number of samples that may be mounted at any one time to be noted in the tender. Angular dependent Torque Magnetometry. a) For this option, a sample size of up to 2 x 2 mm2 should be possible. b) The RMS torque noise level should be better than 2 x 10-9 Nm over a 3.0s sampling time. Computer Control. a) Computer control of all measurements to be provided. Evaluation criteria will be: ease of use, data processing provided, possibility to interface measurement control with software of our own design.