### Abstract

Magnetic form factors have been obtained from Dirac-Fock calculations for all the rare-earth tripositive ions. In addition to using relativistic 4f wave functions, the coupling of the neutron magnetic moment to the current density has been treated consistently using a relativistic formulation for the scattering amplitude. For each rare-earth ion we evaluated the odd magnetic multipoles, of order less or equal to seven, which are needed for the evaluation of the magnetic scattering amplitude in most cases of experimental interest. We find that in all cases the magnetic form factor decreases faster with increasing scattering angle than predicted by nonrelativistic calculations. This is because (i) the relativistic 4f-electron wave functions are more expanded in space as a result of the relativistic core contraction than the Hartree-Fock wave functions and (ii) the net effect of the spin orbit and mass correction term on the scattering of neutrons, implicitly included in our relativistic formulation of the scattering amplitude, is such that the neutron senses a current density more expanded in space than predicted by nonrelativistic calculations.

Original language | English |
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Pages (from-to) | 369-376 |

Number of pages | 8 |

Journal | Physical Review B |

Volume | 15 |

Issue number | 1 |

DOIs | |

Publication status | Published - 1977 |

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### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

*Physical Review B*,

*15*(1), 369-376. https://doi.org/10.1103/PhysRevB.15.369

**Relativistic magnetic form factors of tripositive rare-earth ions.** / Stassis, C.; Deckman, H. W.; Harmon, B. N.; Desclaux, J. P.; Freeman, Arthur J.

Research output: Contribution to journal › Article

*Physical Review B*, vol. 15, no. 1, pp. 369-376. https://doi.org/10.1103/PhysRevB.15.369

}

TY - JOUR

T1 - Relativistic magnetic form factors of tripositive rare-earth ions

AU - Stassis, C.

AU - Deckman, H. W.

AU - Harmon, B. N.

AU - Desclaux, J. P.

AU - Freeman, Arthur J

PY - 1977

Y1 - 1977

N2 - Magnetic form factors have been obtained from Dirac-Fock calculations for all the rare-earth tripositive ions. In addition to using relativistic 4f wave functions, the coupling of the neutron magnetic moment to the current density has been treated consistently using a relativistic formulation for the scattering amplitude. For each rare-earth ion we evaluated the odd magnetic multipoles, of order less or equal to seven, which are needed for the evaluation of the magnetic scattering amplitude in most cases of experimental interest. We find that in all cases the magnetic form factor decreases faster with increasing scattering angle than predicted by nonrelativistic calculations. This is because (i) the relativistic 4f-electron wave functions are more expanded in space as a result of the relativistic core contraction than the Hartree-Fock wave functions and (ii) the net effect of the spin orbit and mass correction term on the scattering of neutrons, implicitly included in our relativistic formulation of the scattering amplitude, is such that the neutron senses a current density more expanded in space than predicted by nonrelativistic calculations.

AB - Magnetic form factors have been obtained from Dirac-Fock calculations for all the rare-earth tripositive ions. In addition to using relativistic 4f wave functions, the coupling of the neutron magnetic moment to the current density has been treated consistently using a relativistic formulation for the scattering amplitude. For each rare-earth ion we evaluated the odd magnetic multipoles, of order less or equal to seven, which are needed for the evaluation of the magnetic scattering amplitude in most cases of experimental interest. We find that in all cases the magnetic form factor decreases faster with increasing scattering angle than predicted by nonrelativistic calculations. This is because (i) the relativistic 4f-electron wave functions are more expanded in space as a result of the relativistic core contraction than the Hartree-Fock wave functions and (ii) the net effect of the spin orbit and mass correction term on the scattering of neutrons, implicitly included in our relativistic formulation of the scattering amplitude, is such that the neutron senses a current density more expanded in space than predicted by nonrelativistic calculations.

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U2 - 10.1103/PhysRevB.15.369

DO - 10.1103/PhysRevB.15.369

M3 - Article

VL - 15

SP - 369

EP - 376

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 1

ER -