Eur. Phys. J. B 66, 155-163 (2008)
https://doi.org/10.1140/epjb/e2008-00411-7

¹⁹F nuclear spin relaxation and spin diffusion effects in the single-ion magnet LiYF₄:Ho³⁺

¹ Physics Department, Kazan State University, Kazan, 420008, Russian Federation
² Department of Physics, Boston College, Chestnut Hill, MA, 02467, USA
³ Department of Physics “A. Volta”, CNR-INFM Unit and CNISM Unit, Pavia 27100, and S3-CNR-INFM, Modena, Italy
⁴ Institute of General Physiology and Biological Chemistry, University of Milano, 20134 Milano, Italy
⁵ St. Petersburg State University of Information Technology, Mechanics and Optics, 199034 St. Petersburg, Russian Federation
⁶ Institut Néel, Département Nanosciences, CNRS, 38042 Grenoble Cedex 09, France

Corresponding author: ^a boris.malkin@ksu.ru

Received: 9 July 2008
Revised: 15 August 2008
Published online: 14 November 2008

Abstract

Temperature and magnetic field dependences of the ¹⁹F nuclear spin-lattice relaxation in a single crystal of LiYF₄ doped with holmium are described by an approach based on a detailed consideration of the magnetic dipole-dipole interactions between nuclei and impurity paramagnetic ions and nuclear spin diffusion processes. The observed non-exponential long time recovery of the nuclear magnetization after saturation at intermediate temperatures is in agreement with predictions of the spin-diffusion theory in a case of the diffusion limited relaxation. At avoided level crossings in the spectrum of electron-nuclear states of Ho^{3 +} ions, rates of nuclear spin-lattice relaxation increase due to quasi-resonant energy exchange between nuclei and paramagnetic ions in contrast to the predominant role played by electronic cross-relaxation processes in the low-frequency ac-susceptibility.