Low Temperature Studies Section

 LTSS is mainly involved in the investigation of Transport and Magnetic properties of Superconductors, Strongly Correlated Electron Systems and other novel materials. Measurements are done at Low Temperatures   under High Magnetic Field or Pressure. The intention of the laboratory is to make new materials and study their electronic and magnetic ground states.

Ranging from Box and Arc Melting Furnaces to a Argon filled Glove Box, the laboratory is equipped with several synthesis facilities.  The laboratory has consistently worked on superconducting materials since its inception in 1974. From A15 compounds, chevral phase compounds, high TC superconductors, fullerenes, MgB₂ and more recently the arsenide superconductors, the laboratory has continuously engaged in making new materials.

Recently we have been able to grow single crystalline samples of BaFe₂As₂ samples by slow cooling from high temperature. Superconducting crystals were made by substituting Co or Ru at the Fe site. The members have also acquired the skill of making transport and magnetic measurements on tiny single crystals. This  has enabled the group to address important issues of H_C2 and J_C anisotropy in these single crystals.

The highlight of our investigation using polycrystals was the discovery of superconductivity in BaFe_2-xRu_xAs₂ system for the first time in literature. Based on temperature dependent resistivity we were able to draw  the magnetic/superconducting phase diagram as function of Ru substitution.

Being now equipped  with a Pulsed Laser Deposition system, we are able to grow  thin films. We have been able to grow superconducting thin films of the newly discovered FeSe_0.5Te_0.5 superconductor. Several thin films of charge ordered manganate (Pr0.5Ca0.5MnO3) were grown on Mgo substrates, in which we observed strain induced charge ordered insulator to metal transition.

Facilities to carryout Transport property measurements at pressures up to 7.5GPa, were developed in house in 1989.Using the high pressure resistivity apparatus we were able to show the occurence of superconductivity in undoped single crystalline BaFe₂As₂ at a small pressure of 1.5 GPa.

 The magnetoresistance apparatus and the vibrating sample magnetometer are routinely used to characterise the samples. The capability  magnetic fields are up to 12 T in the magneto-resistant cryostat. The magnetisation measurements are in the temperature range 2K- 600K in field upto 16 Tesla.  

An ac susceptibility system attached the VSM is helpful to study magnetic dynamics. Based on this apparatus we were recently able to investigate the dynamics of a dense nano particle assembly of Ni nano particles.