Anomalous magnetic field dependence of TAF in La0.95Sr0.05MnO3
Experimentalphysik III, Institut für Physik, Universität Augsburg, 86159 Augsburg, Germany
2 General Physics Institute of the Russian Acad. Sci., 117942 Moscow, Russia
Corresponding author: a email@example.com
Published online: 15 February 2001
The magneto-elastic properties of single-crystalline La0.95Sr0.05MnO3 have been studied ultrasonically. Our investigations focussed on the temperature interval where magnetic ordering starts to evolve and results in a spin canted antiferromagnetic ground state. In detail the experiments revealed that the magnetic order parameter in low-doped manganite is only weakly coupled to lattice strains. Furthermore, the anomalous temperature dependence of the order parameter as found resembles highly that in stoichiometric LaMnO3. However, the main and most surprising finding is that external magnetic fields favor the spin canted phase in La0.95Sr0.05MnO3. It is unclear at present how the exchange interaction can be tuned by magnetic fields in the way observed and we are not aware of existing theoretical concepts which might give a plausible explanation for the unexpected field dependent behavior of the critical temperature. We believe, however, that this behavior primarily results from the fact that the exchange interaction depends sensitively on the orbital configuration of the manganese d electrons.
PACS: 75.50.Ee – Antiferromagnetics / 62.65.+k – Acoustical properties of solids / 75.40.Cx – Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001