Anisotropic Cascade of Field-Induced Phase Transitions in the Frustrated Spin-Ladder System ${\mathrm{BiCu}}_{2}{\mathrm{PO}}_{6}$

Anisotropic Cascade of Field-Induced Phase Transitions in the Frustrated Spin-Ladder System ${BiCu}_{2} {PO}_{6}$

Yoshimitsu Kohama, Shuang Wang, Atsuko Uchida, Krunoslav Prsa, Sergei Zvyagin, Yuri Skourski, Ross D. McDonald, Luis Balicas, Henrik M. Ronnow, Christian Rüegg, and Marcelo Jaime

Phys. Rev. Lett. 109, 167204 – Published 17 October 2012

Abstract

${BiCu}_{2} {PO}_{6}$ is a frustrated two-leg spin-ladder compound with a spin gap that can be closed with a magnetic field of approximately 20 T. This quantum phase transition and its related phase diagram as a function of magnetic field and temperature ( $H$ , $T$ ) are investigated up to 60 T by means of specific heat, magnetocaloric effect, magnetization, and magnetostriction measurements. In contrast to other gapped quantum magnets, ${BiCu}_{2} {PO}_{6}$ undergoes a series of unexpected first- and second-order phase transitions when an external magnetic field is applied along the crystallographic $c$ axis. The application of a magnetic field along the $b$ axis induces two second-order phase transitions. We propose that the anisotropy and complex phase diagram result from the interplay between strong geometrical frustration and spin-orbit interaction necessary for the description of this fascinating magnetic system.

Received 17 July 2012

DOI:https://doi.org/10.1103/PhysRevLett.109.167204

Authors & Affiliations

Yoshimitsu Kohama¹, Shuang Wang^2,3, Atsuko Uchida¹, Krunoslav Prsa², Sergei Zvyagin⁴, Yuri Skourski⁴, Ross D. McDonald¹, Luis Balicas⁵, Henrik M. Ronnow², Christian Rüegg^6,7,8, and Marcelo Jaime¹

¹MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
²Laboratory for Quantum Magnetism, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland
³Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
⁴Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
⁵National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
⁶London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, United Kingdom
⁷Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
⁸DPMC-MaNEP, University of Geneva, CH-1211 Geneva, Switzerland