Competition between the <math>;Cr3+-Gd3+</math> Direct Exchange and Superexchange in <math>Cr</math> Doped <math>; GdA103</math>

Physics NotePublished

Competition between the $<math>\;Cr^{3+}-Gd^{3+}</math>$ Direct Exchange and Superexchange in $<math>Cr</math>$ Doped $<math>\; GdA10_3</math>$

M. del Castillo Mussot; D. Guenzburger; J. S. Helman

1990

Authors: M. del Castillo Mussot; D. Guenzburger; J. S. Helman
Type: Physics Note
Status: Published
Publication date: 1990
Description: The temperature dependence of the fluorescence spectrum of <math>\;Cr^{3+}</math> diluted impurities in <math>\;GdA10_3</math> and the magnetic Franck-Condon effect observed in this system indicate that the exchange coupling constant <math>J_E\,\!</math> between <math>\;Cr^{3+}</math> in the <math>^2E\,\!</math> excited state and <math>\;Gd^{3+}</math> is very small, in the sense that <math>\;|J_E|<<J_g</math>, where<math>\;J_g</math> is the exchange coupling constant between <math>\;Cr^{3+}</math> in the ground state <math>\;^4A_2</math> and <math>\;Gd^{3+}</math>. Here this is interpreted as resulting from a cancellation between the ferromagnetic direct <math>\;Cr^{3+}Gd^{3+}</math> exchange interaction and the antiferromagnetic superexchange which takes place through the oxygen ions.
Year: 1990
Number: CBPF-NF-016/90
Linked to a thesis: No
Linked to a grant: No