Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 11: Magnetic Materials
MA 11.10: Vortrag
Montag, 23. März 2009, 17:45–18:00, HSZ 103
Coupling between Ho and Cr magnetic sub lattice in rare-earth orthochromite HoCrO3 — •Naveen Kumar Chogondahalli M.1, Yinguo Xiao1, Yixi Su2, Jörg Perßon1, Anatoliy Senyshyn3, and Thomas Brückel1,2 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Jülich Centre for Neutron Science, IFF, Forschungszentrum Jülich, Outstation at FRM II, 85747 Garching, Germany — 3Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), 85747 Garching, Germany
HoCrO3 crystallizes in orthorhombic structure with the space group Pbnm in the temperature range 4 to 300 K. Both the magnetization and heat capacity measurements clearly indicate the onset of magnetic ordering at TN =140 K. From Curie-Weiss fit of magnetic susceptibility, the Curie temperature is found to be -28.81 K and the effective moment, Peff = 15.78 bohr magneton. The temperature dependence of magnetic structure is investigated by using the neutron powder diffraction. Below Neel temperature Cr3+ orders antiferromagnetically with the moments aligned along c-axis. The canted ferromagnetic ordering of Ho3+ with moments aligned perpendicular to Cr3+ moments is observed at lower temperatures. The molecular field of Cr cancels at Ho site. It is likely that the ordering of Ho is induced by the fluctuations of Cr subsystem magnetization but not by magnetization itself. This may be order by disorder type of induced ordering [J. Villain et al., 1980]. Such an ordering is only possible if the resulting interactions, Cr-Ho is much stronger than Ho-Ho antiferromagnetic exchange.