Articles

November 4, 2011 12:14 PM

 Diagram of the diamond anvil cell experiment

An amorphous diamond—one that lacks the crystalline structure that makes diamonds cleavable, but is every bit as hard—has been created by a team of researchers using a High Pressure Collaborative Access Team x-ray beamline at the U.S. Department of Energy Office of Science’s Advanced Photon Source.
http://www.aps.anl.gov/Science/Highlights/Content/APS_SCIENCE_20111026C.php
 

September 19, 2011 10:45 AM

Phonon DOS and pDOS of ordered FeV (green) are clearly softened compared to the disordered phase (black).      

September 19, 2011 05:25 PM

Novel Magnetic Material operates under Extreme Stress Conditions

See: D. Haskel, G. Fabbris N. M. Souza-Neto, M. van Veenendaal,  G. Shen, A. E. Smith, M. A. Subramanian, “Stability of the ferromagnetic ground state of oxide insulator La2MnNiO6 against large compressive stress,” Phys. Rev. B 84, 100403 (2011)

June 23, 2011 05:40 PM

Researchers Xiao-Jia Chen, Viktor Struzhkin, and Ho-Kwang Mao from Carnegie and Yue Meng from HPCAT, along with collaborators from China, designed delicate experiments to obtain a complete high-pressure phase diagram of compressed Ge. Their results, published in Physical Review Letters, show that under a pressure of 66 GPa, Ge undergoes a structural change from a metallic white tin structure to an orthorhombic Imma structure. It then undergoes another change under pressure of 90 GPa to the simple hexagonal structure.

June 17, 2011 03:29 PM

 

April 27, 2011 10:03 AM

Phase Diagram of lithium

April 27, 2011 09:56 AM

Pressure dependence of the molar volume of SiO2 glass with helium loading in this work and without helium from literature data. The thick black line represents the equation of states of crystalline polymorphs of SiO2.

April 18, 2011 02:28 PM

To assess the usefulness of high-entropy alloys based on equimolar FeCoCrNi for magnetic application at high temperature, magnetic and vibrational properties of such materials were measured using vibrating sample magnetometry and nuclear resonant inelastic X-ray scattering. The HPCAT experiments show that the Fe partial phonon density of states of FeCoCrNi is similar to that of FeNi which has the same fcc structure. By adding the heavier Pd to the alloy, the mode energy of iron is decreased. The high energy optical modes between 40-50meV in FeCoCrNiAl2 indicated chemical ordering and formation of an Al-rich sublattice, which also confirmed by XRD experiments. High-entropy alloys based on FeCoCrNi were found to be poor candidates for soft magnetic applications, especially at elevated temperatures.
Lucas et al. J. Appl. Phys. 109, 07E307 (2011)