NMR study of size effects in relaxor PMN nanoparticles

• Published in: Physica Status Solidi (b) Vol. 248; no. 11; pp. 2653 - 2655
• Main Authors: Blinc, Robert, Zalar, Boštjan, Zupančič, Blaž, Morozovska, Anna N., Glinchuk, Maya D.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.11.2011; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Frozen; Line shape; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Materials science; Nanocrystals; Nanoparticles; NMR; Nuclear magnetic resonance; Nuclear magnetic resonance and relaxation; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Quadrupoles; Relaxors; size effect; Spin-lattice relaxation; Nanoparticles; Chemical shift; Line shape; Phase transformations; Spin-lattice relaxation; Size effect; Long-range order; Ordering; Relaxor; Nuclear magnetic resonance; Nanocrystal; Lead magnesium niobates
• ISSN: 0370-1972; 1521-3951; 1521-3951
• DOI: 10.1002/pssb.201100055

93Nb ${1 \over 2}$ → −${1 \over 2}$ NMR line shape and spin–lattice measurements show that microcrystalline PbMg1/3Nb2/3O3 (PMN) powder is dynamically disordered at room temperature, whereas nanocrystalline PMN powder is orientationally frozen out and long‐range ordered at room temperature. The dynamical disorder of the microcrystalline powder results in a motional averaging of the anisotropic part of the 93Nb chemical shift tensor and second order quadrupole shift, whereas this averaging is absent in the nanocrystalline powder, resulting in a broader central line and a longer spin–lattice relaxation time. This seems to be the first observation of such size effects in a relaxor.