NMR in ferromagnetic manganites

Pavel Novak 1Michail M. Savosta 2

1. Czech Academy of Sciences, Institute of Physics, Cukrovarnicka 10, Prague 16253, Czech Republic
2. National Academy of Sciences of Ukraine, A.Galkin Donetsk Institute for Physics & Technology (DonPTI NASU), Roza Luxemburg 72, Donetsk 83114, Ukraine

Abstract

Nuclear magnetic resonance is a suitable tool to provide insight in the nature of the complex physics of the ferromagnetic manganites as it probes locally the magnetic states and their dynamics. The combination of NMR and dc magnetization studies proved to be of particular importance when determining the nature of the magnetic transition.

In this work we present selected results of an extensive study of the temperature dependence of 55Mn nuclear magnetic resonance and relaxation in the mixed valence ferromagnetic manganites, completed in several cases by the 139La NMR and dc magnetization measurements. In particular the crossover between the second- and first- order magnetic transition in La0.7M0.3MnO3 (M=Ca, Sr, Ba) manganites is analysed and the temperature dependence of the spin-lattice and spin-spin nuclear relaxation in La1-xNax MnO3 system is used to determine the polaronic nature of the charge carriers. NMR evidence of the magnetic phase separation in ferromagnetic manganites is also given and the charge density wave in La0.84Sr0.16MnO3 is revealed.

 

Presentation: invited oral at E-MRS Fall Meeting 2003, Symposium D, by Pavel Novak
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-06-03 15:20
Revised:   2009-06-08 12:55