Our newer XRD system, the X-ray diffraction facility includes a SmartLab® high-resolution 3 kW X-ray diffractometer for Powder diffraction, thin film diffraction, and in-plane scattering. The system is also equipped with a PDXL software suite which "is a one-stop full-function powder diffraction analysis software suite". "PDXL provides various analysis tools such as automatic phase identification, quantitative analysis, crystallite-size analysis, lattice constants refinement, Rietveld analysis, ab initio structure determination, etc."

Further information regarding the SmartLab® system can be obtained at www.rigaku.com/products/xrd/smartlab

Raman Scattering Facility

The dispersive Raman scattering facility includes a model T 64000 Jobin Yvon triple monochromator system (left), equipped with an optical multichannel detector (CCD array), a photomultiplier detector and a microscope attachment to examine the scattering on a spatial resolution of 2 microns or less. A variety of lines to excite the Raman scattering are accessible from a Kr-ion or an Ar-ion laser. Low-T micro-Raman measurements are routinely performed using a Joule-Thompson refrigerator (MMR - model R2300). The figure on the right displays a Raman spectrum of GeSe₂ glass taken with a 647.1nm exciting line.

Vibrating Sample Magnetometer

DC Magnetization measurements are performed using a EG & G PAR model 4500, Vibrating Sample Magnetometer system (left) equipped with a 1 Tesla Electromagnet . Details of the He-cryosystem mounting (using an APD CS-202 W with a DMX-19 interface) to cool samples to 10K are visible in the figure on the right . The metal framework supports the He cryocooler which vibrates because of the motor in the cold head. The sample supported from the VSM head (which rests on the heavy magnet), hangs in an exchange gas column in the DMX-19 interface, and is thus mechanically isolated from the vibration-prone He-cryocooler.

Mössbauer Spectroscopy

A standard liquid Helium cryostat with an 8 T superconducting magnet and an exchange gas column for inserting a vertical drive assembly is used for Mössbauer spectroscopy measurements at 4.2K. The development of an adequate mounting method in the early 80's, here in our own laboratory to achieve truly vibration - free He-cryocoolers opened the way to perform Mössbauer spectroscopy measurements in the 10K < T < 300K range without the need of liquid cryogens. The figure on the left displays the mounting method used for an APD Inc. CS202W He - cryocooler with DMX-20 interface. The figure on the right displays Mössbauer spectrum of the inner two lines of alpha-Fe taken with te compressor on and off. No change in the full-width at maximum of the lines is observed upon switching on the compressor indicating the truly vibration-free performance of the He cryocooler assembly. Details of the mount can be obtained from [9]. Three such spectrometers are used in the laboratory for T-dependent work on glasses and high-Tc superconductors.

Thermal Analysis Equipment

        

In our laboratory, the work horse for Tg measurements on glasses over the past two decades has continued to be a DSC model 2C instrument from Perkin-Elmer. More recently we have added TGA7 and a DMA7 unit from Perkin Elmer to characterize oxygen weight loss in cuprate semiconductors and alpha- and beta- relaxation in network glasses respectively.

Magnetron Sputter-Deposition of Thin Films

Two US guns (one RF and the other DC) with provisions for 2" targets have been incorporated in a Cooke Vacuum system model CVE-600MC, which includes a steel bell jar assembly, a CT-8 He cryogenic pump from CTI-Cryogenics and associated pressure gauges and monitors. Provision for heating the substrate up to 700 C during deposition is made possible by a conducting heater block. The system has been used to deposit [10], [11] high-Tc thin films of YBCO both on-axis and off-axis. The system is now being adapted to deposit CdS and LaS films. The figure on the right displays an optical micrograph of LaS single crystals prepared by a two-step synthesis of the elements.