Facilities

Dilution
Helium-3
Helium-4
Sample handling
Pressure
Characterization
Growth

DILUTION REFRIGERATION SCANNING PROBE MICROSCOPIES

Scanning Tunneling Microscope with high resolution, down to 100 mK and 9 T. Home made gas handling system, and modified fridge based on Kelvinox 25 of Oxford. Coil of Janis Research.

Here we study thin superconducting films, two gap and related superconductors, and vortex physics.

Some details about this facility are given in this paper. The set-up has an in-situ sample breaking system and a pad for tip preparation.

 

Scanning Tunneling Microscopy under current flow. Dilution refrigerator going down to 7 mK, 9 T. Modified MX400 of Oxford.

Here we study superconducting thin films, heavy fermions and other superconducting sytems. Sometimes we use superconducting tips. In thin films and conventional superconductors, we focus on the behavior of superconducting vortices under current flow. This method, similar in some respects to scanning potentiometry, allows tunneling imaging when a current flows through the sample.

More details about this experiment can be found here.

 

Three axis magnet Scanning Tunneling Microscopy. 50 mK, Three axis coil 5+1+1 T. Modified MX50 of Oxford, home made gas handling system. Home made coil.

Here we measure dicalchogenides, borocarbides and other multiple gap superconducting systems. The set-up has an in-situ sample breaking system and a pad for tip preparation.

 

 

 

 

Force and magnetic probe microscopies. Dilution refrigerator going down to 7 mK, 9 T. Modified MX400 of Oxford.

Here we are setting up force and magnetic scanning probe microscopies.

 

 

 

 


HELIUM-3 SCANNING PROBE MICROSCOPIES

Scanning Tunneling Spectroscopy using superconducting tips. 250 mK, 13 T. Heliox of Oxford.

This set-up is specifically designed to use superconducting tips of Pb. Different systems are probed using this method, such as dicalchogenides, thin films close to the superconductor-insulator transition, and Pb nanostructures.

 

 

Atomic Force Microscopy and Scanning Tunneling Microscopy and Spectroscopy on single molecules. 250 mK, 9 T. Heliox of Oxford.

This set-up is specifically designed to measure systems of isolated single molecules or deposited molecular layers.

 

 

 

 

250 mK system with 17 T magnet.

This set-up is under construction. Magnetic field of 15 T has been obtained recently (April 2012) in our laboratory.

 

 

 

 

 

 

 


HELIUM-4 SYSTEMS

The LBTUAM runs eight low consumption helium-4 systems with different experiments, such as tunneling microscopy, specific heat, thermal expansion, and other thermal properties. Small home-made superconducting coils of up to 2 T are used to apply magnetic fields.

For example, a low-temperature, home-made calorimetric experimental system, either in cryogenic environments at liquid helium temperatures, or at temperatures above that of liquid nitrogen. Calorimetric measurements are conducted by using a versatile computer program developed in the lab, that allow us to choose among four different calorimetric methods: (i) the classical adiabatic method; (ii) the standard low-temperature relaxation method; (iii) an alternative fast relaxation method; (iv) a quasi-adiabatic continuous method to monitor and characterize phase transitions at higher temperatures.

 


SAMPLE HANDLING

We use several binoculars and optical systems to mount sample and tip. We also use one metallurgical microscope, and fast room temperature AFM. We have vacuum vessels and one large glove box to handle complex or oxydizing materials.

 

 

 

 


 HIGH PRESSURE EXPERIMENTS

We use two high pressure cells, built at the workshop of our University in collaboration with our late friend V. Tissen (Moscow), who visited several times our lab and the ICMM, within the Unidad Asociada. These cells are capable of reaching up to 30 GPa, and are suitable for being used in the PPMS facility of the ICMM, which cools down to 2 K with fields of 10 T, as well as in our dilution and 3He fridges, with magnetic fields up to 17 T.

 

 

 


FAST SAMPLE CHARACTERIZATION

The LBTUAM develops a sample characterization set-up to measure resistivity, specific heat, thermal conductivity and other materials properties to test new samples.

 

 

 


SAMPLE GROWTH

A basic flux single crystalline sample growth bench has been set-up together with P.C. Canfield (Ames) within a teaching project of the Master degree. The bench consists of a torch and several ovens. This project was financed with the collaboration of Banco Santander.

 

 

 


 

OUR NICE CAMPUS