Group Meeting, Fridays at 10:30AM in the Butterfly Room
- Our laboratory is equipped with several liquid 4He systems that can reach temperatures as low as 1.8 K in magnetic fields as high as 11 Tesla.
- We also operate a 3He system that can achieve 280 mK at a field of up to 5 Tesla, and is equipped with low-T mu-metal shield for field shielding <0.02 Oe.
- For ultra-low temperatures we are using a Cryogen-Free Dilution Refrigerator Model CF-CS81-1600-Maglev from Leiden Cryogenics, equipped with a 9-1-1 Tesla vector magnet.
- We operate a 4He continuous flow probe system.
Our STM system is a hybrid of home design platform with a UNISOKU USM1300 STM system. This system operates at UHV conditions (<1x10-10 torr), Low Temperatures (base temperature 0.33K), and high magnetic field (up to 12 tesla), with extra-large liquid helium capacity for long scans. The magnet system was designed by us and fabricated by AMI Inc., to achieve uniform field at the STM head, while also compensating the high field outside the cryostat. This allows for a unique vibration isolation scheme utilizing “Minus-K” leg-platforms.
The STM system is served by:
i) UHV preparation chamber (<1x10-10 torr), equipped with a fast load-lock chamber, RGA, ion gun, and heating system;
ii) A specialized cleaving chamber with easy removal of cleaving debree;
iii) A mini MBE system which includes two mini effusion cells, QCM thickness monitoringbsystem, and pyrometric system for monitoring of substrate temperature (substrate temperature can be controlled up to 1200 oC.
One of our unique capabilities is the ability to measure non-reciprocal effects in transmission or reflection of linearly polarized light to a resolution of better than 70 nanorad/pHz at 20 μWatt incident power. The stability of the device was demonstrated to be better than ±10 nanorad over 35 hours at a constant temperature, and better than 30 nanorad over a temperature range of 0.3 - 300 K. This apparatus led to the important observation of broken time reversal symmetry breaking effect in Sr2RuO4 with a maximum signal of 65 nanorad, a result never measured before. We also operate a 4He continuous flow Sagnac apparatus with scanning capability, temperature range of 5K to room temperature and a small magnetic field up to 1 kOe.
Photo-thermal Apparatus for Thermal Diffusivity Measurements:
In the standard measurement configuration, a focused laser beam heats locally the face of the sample, while its power being modulated at a frequency in the range 200 Hz to 50 kHz. A second beam, r distance from it measures the phase delay of the heat wave, ". The thermal diffusivity is then extracted from the relation between the phase delay and the other parameters. We can measure down to 5 K and up to 650 K.