J1J2 square lattice antiferromagnetism in the orbitally quenched insulator MoOPO4

L. Yang, M. Jeong, P. Babkevich, V. M. Katukuri, B. Náfrádi, N. E. Shaik, A. Magrez, H. Berger, J. Schefer, E. Ressouche, M. Kriener, I. Živković, O. V. Yazyev, L. Forró, and H. M. Rønnow
Phys. Rev. B 96, 024445 – Published 28 July 2017

Abstract

We report magnetic and thermodynamic properties of a 4d1 (Mo5+) magnetic insulator MoOPO4 single crystal, which realizes a J1J2 Heisenberg spin-1/2 model on a stacked square lattice. The specific-heat measurements show a magnetic transition at 16 K which is also confirmed by magnetic susceptibility, ESR, and neutron diffraction measurements. Magnetic entropy deduced from the specific heat corresponds to a two-level degree of freedom per Mo5+ ion, and the effective moment from the susceptibility corresponds to the spin-only value. Using ab initio quantum chemistry calculations, we demonstrate that the Mo5+ ion hosts a purely spin-1/2 magnetic moment, indicating negligible effects of spin-orbit interaction. The quenched orbital moments originate from the large displacement of Mo ions inside the MoO6 octahedra along the apical direction. The ground state is shown by neutron diffraction to support a collinear Néel-type magnetic order, and a spin-flop transition is observed around an applied magnetic field of 3.5 T. The magnetic phase diagram is reproduced by a mean-field calculation assuming a small easy-axis anisotropy in the exchange interactions. Our results suggest 4d molybdates as an alternative playground to search for model quantum magnets.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 17 May 2017

DOI:https://doi.org/10.1103/PhysRevB.96.024445

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

L. Yang1,2, M. Jeong1,*, P. Babkevich1, V. M. Katukuri3, B. Náfrádi2, N. E. Shaik1, A. Magrez4, H. Berger4, J. Schefer5, E. Ressouche6, M. Kriener7, I. Živković1, O. V. Yazyev3, L. Forró2, and H. M. Rønnow1,7,†

  • 1Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Féderale de Lausanne, CH-1015 Lausanne, Switzerland
  • 2Laboratory of Physics of Complex Matter, Institute of Physics, Ecole Polytechnique Féderale de Lausanne, CH-1015 Lausanne, Switzerland
  • 3Chair of Computational Condensed Matter Physics, Institute of Physics, Ecole Polytechnique Féderale de Lausanne, CH-1015 Lausanne, Switzerland
  • 4Crystal Growth Facility, Institute of Physics, Ecole Polytechnique Féderale de Lausanne, CH-1015 Lausanne, Switzerland
  • 5Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
  • 6Université Grenoble Alpes, CEA, INAC, MEM, F-38000 Grenoble, France
  • 7RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan

  • *minki.jeong@gmail.com
  • henrik.ronnow@epfl.ch

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 96, Iss. 2 — 1 July 2017

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×