Low temperature magnetic properties of frustrated pyrochlore ferromagnet Ho2Ir2O7

8th International Conference on Highly Frustrated Magnetism 2016

Kumar, Dinesh^1 ; Chen, S.Y.^1 ; Lee, M.K.^1 ; Kumar, C.M.N.^2,3 ; Aldus, R.^2 ; Chang, L.J.^1

Department of Physics, National Cheng Kung University, No. 1, University Road, Tainan

70101, Taiwan^1

Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, United States, Oak Ridge

TN

37831, United States^2

Laboratoire National des Champs Magnetiques Intenses CNRS, 143, avenue de Rangueil, Toulouse

F-31400, France^3

关键词: Antiferromagnetics;    Doublet ground state;    Heat-capacity data;    Low temperatures;    Magnetic components;    Magnetization measurements;    Neutron diffraction measurements;    Neutron diffraction spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/828/1/012008/pdf
DOI  :  10.1088/1742-6596/828/1/012008

来源: IOP

【 摘 要 】

We have performed low temperature magnetic susceptibility, specific heat, electrical resistivity and neutron diffraction measurements to study the magnetic properties of frustrated pyrochlore ferromagnet Ho2Ir2O7. The magnetization and dc resistivity measurement indicate metal-insulator transition near 140 K. The accumulated value of observed entropy calculated from heat capacity data is Rln2, indicating the Ho3+doublet ground state. The Ir sublattice order is antiferromagnetic which is evident from the magnetization measurements. The best fit of the neutron diffraction spectra at 1.8 K shows the magnetic structures with two types of components. One of the magnetic structure is all-in-all-out type, which is due to the strong coupling between Ho3+and Ir4+ions and develops below 18 K. It suggests that the magnetic moment of Ho3+ions align in the field of Ir4+, ordering along localdirections. There is also a Ho3+magnetic component perpendicular tobelow 100 K. This perpendicular component may originate from the defects in the Ir sub-lattice. Defects such as Ir deficiency or an Ir atom pointing at the opposite direction will cause the emergent of the perpendicular component.