Origin of magnetic moments and presence of spin-orbit singlets in Ba2YIrO6

Abhishek Nag, Sayantika Bhowal, Atasi Chakraborty, M. M. Sala, A. Efimenko, F. Bert, P. K. Biswas, A. D. Hillier, M. Itoh, S. D. Kaushik, V. Siruguri, C. Meneghini, I. Dasgupta, and Sugata Ray
Phys. Rev. B 98, 014431 – Published 26 July 2018
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Abstract

While it was speculated that 5d4 systems would possess nonmagnetic J=0 ground state due to strong spin-orbit coupling (SOC), all such systems have invariably shown the presence of magnetic moments so far. A puzzling case is that of Ba2YIrO6, which in spite of having a perfectly cubic structure with largely separated Ir5+(d4) ions, has consistently hosted weak magnetic moments. We show from muon spin relaxation (μSR) measurements that a change in the magnetic environment of the implanted muons in Ba2YIrO6 occurs as the temperature is lowered below 10 K indicating magnetic response has a temperature dependence unlikely for a J=0 system. Interestingly, the estimated value of SOC obtained by fitting the resonant inelastic x-ray scattering (RIXS) spectrum of Ba2YIrO6 with an effective atomic many-body Hamiltonian is found to be as high as 0.39 eV, comparable to the reported value of SOC in other magnetic d4 iridates with noncubic distortion. We argue that in addition to strong SOC, the presence of intersite hopping triggers delocalization of holes, resulting in the spontaneous generation of magnetic moments. Our theoretical calculations further indicate that these moments favor the formation of spin-orbital singlets in the case of Ba2YIrO6, which is manifested in μSR experiments measured down to 60 mK.

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  • Received 21 July 2017
  • Revised 1 November 2017

DOI:https://doi.org/10.1103/PhysRevB.98.014431

©2018 American Physical Society

Physics Subject Headings (PhySH)

  1. Research Areas
Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Abhishek Nag1, Sayantika Bhowal2, Atasi Chakraborty2, M. M. Sala3, A. Efimenko3, F. Bert4, P. K. Biswas5, A. D. Hillier5, M. Itoh6, S. D. Kaushik7, V. Siruguri7, C. Meneghini8, I. Dasgupta2,9, and Sugata Ray1,9,*

  • 1Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
  • 2Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
  • 3ESRF–The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
  • 4Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
  • 5ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX110QX, United Kingdom
  • 6Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503, Japan
  • 7UGC-DAE Consortium for Scientific Research, Mumbai Centre, Bhabha Atomic Research Centre, Mumbai 400085, India
  • 8Dipartimento di Scienze, Universitá Roma Tre, Via della Vasca Navale, 84 I-00146 Roma, Italy
  • 9Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India

  • *mssr@iacs.res.in

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Issue

Vol. 98, Iss. 1 — 1 July 2018

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