Karl Gschneidner of Ames Laboratory Passed Away

May 23, 2016 (PO45).  Karl A. Gschneidner Jr., known internationally as Mr. Rare Earth, passed away on April 27, 2016, at the age of 85.  Gschneidner began work on his Ph.D. at Iowa State University (Ames, Iowa, USA) in 1955 while working as Ames Laboratory graduate researcher in metallurgy. After receiving his doctorate from Iowa State in 1957, he took a job in the Chemistry and Metallurgy Division of Los Alamos National Laboratory in Los Alamos, New Mexico, but returned to Ames in 1963. He formally retired from the Laboratory in January 2016, after a distinguished 60-year career that was dedicated to the study of rare-earth metals.

Among Gschneidner’s important contributions is one of major importance for magnetic refrigeration and cryogenics: the discovery in 1997 of the giant magnetocaloric effect in Gd₅(Si₂Ge₂) [1], which then lead to analogous discoveries in other rare earth compounds and alloys.  While dilution refrigerators largely supplanted adiabatic demagnetization at very low temperatures, the method remains of importance, e.g., in space applications.

Gschneidner was a Distinguished Professor of Materials Science and Engineering at Iowa State University, a Senior Metallurgist at the Ames Laboratory, and the Chief Scientist of the Critical Materials Institute.  He was elected to the National Academy of Engineering and earned a lengthy list of awards for his research.

A prolific writer, he published more than 544 articles in scientific journals and more than 170 chapters in books and conference proceedings.  As a testament to the quality of his research, his published works have been cited an astonishing 19,013 times – an average of 328 citations per year over his career.  It was his renown as “Mr. Rare Earth” that led to the establishment of the Critical Materials Institute, a U.S. Department of Energy Innovation Hub located at the Ames Laboratory.  Gschneidner testified before a Congressional committee about the need for such a research center and later served as the first chief scientist for CMI.

[1] Pecharsky, V. K.; Gschneidner, Jr., K. A.  "Giant Magnetocaloric Effect in Gd₅(Si₂Ge₂)".  
      Phys. Rev. Lett. 78 (23) 4494. doi:10.1103/PhysRevLett.78.4494

This abbreviated text is largely based on the obituary published by the online Ames Laboratory News Center, April 29, 2016.