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2011-07-01T18:09:30Z 2011-07-01T18:09:30Z Slichter, C.P. Abbas, Daniel Cornelius 10000-01-01 1977 We have discovered that the NMR frequencies of Cu atoms which are near neighbors to Cr atoms in dilute CuCr have an anomolous temperature dependence. Comparison with data from CuMn and CuFe which display the normal temperature dependence of a Curie-Weiss law lead us to conclude that an ionic model of the magnetic impurity is necessary to explain the data. We develop a model which assumes a definite 3dn configuration with a definite L-S ground state and includes intraconfigurationa1 energy level splittings due to a crystalline electric field and spin-orbit coupling. We calculate the spin and orbital susceptibilities from the ionic structure and include the effects of the impurity electron-conduction electron mixing interaction in a perturbation treatment. We also calculate the impurity hyperfine fields expected from the mode1+ Comparison of the model predictions with the data lead us to conclude that (a) Cr and Mn have the structure which corresponds to the free ion divalent configuration while Fe corresponds to a monovalent configuration, (b) the crystal field at the site of the magnetic atoms is opposite of that usually assumed, and (c) the Weiss temperature of CuCr is 2.9 ±l.O K which is higher than most previously reported values but agrees within the experimental errors with a recently published bulk magnetic susceptibility measurement. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T18:09:30Z No. of bitstreams: 1 1977_abbas.pdf: 3941978 bytes, checksum: b3012b8373f0bf591d2be2130171831d (MD5) Made available in DSpace on 2011-07-01T18:09:30Z (GMT). No. of bitstreams: 1 1977_abbas.pdf: 3941978 bytes, checksum: b3012b8373f0bf591d2be2130171831d (MD5) Previous issue date: 1977 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-01T18:09:30Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:32:35-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 252689 http://hdl.handle.net/2142/25627 en 1977 Daniel Cornelius Abbas ionic model chromium manganese iron copper Curie-Weiss law magnetic impurity Ionic model for chromium, manganese and iron impurities in copper Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.