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   COLLOQUIUM OF THE LABORATORY FOR COMPUTER DESIGN OF MATERIALS
                   School of Computational Sciences
                           (CSI 898-Sec 001)
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  Magnetic properties and magnetic anisotropy of pure and doped YCo5

                               Paul Larson
              Center for Computational Materials Science
           Naval Research Laborator, Washington, DC  20375

While the magnetic moment and magnetic anisotropy energy (MAE) of 
YCo5 have been studied in the past, our electronic structure 
calculations find several differences from the published results.  
Previous calculations of the MAE for YCo5, using LDA for the 
exchange-correlation potential, have found values significantly 
smaller (~0.6 meV/f.u.) than experiment (~3.8 meV/f.u.).  The rest of 
the MAE is attributed to orbital polarization (OP) effects.  Our
full-potential LAPW calculations using GGA instead of LDA and 
including spherical corrections give values ~1.5 meV/f.u., so a 
significantly smaller portion of the MAE derives from OP effects.  
The MAE in YCo(5-x)Cu(x) has been studied as a function of Cu 
concentration.  Unlike the prediction of the virtual crystal 
approximation, the magnetic moment on the Co sites of YCo(5-x)Cu(x) 
and Y(2)Co(7-x)Ni(x) decrease slowly with impurity concentration
until dropping suddenly to zero at a critical dopant concentration.

                         Monday , February 25, 2002
                                  4:30 pm
                        Room 206, Science & Tech. I

Refreshments will be served at 4:15 PM.
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Find the schedule at http://www.csi.gmu.edu/lcdm/seminar/schedule.html