Tuning the giant magnetoelastic transition in Ba3BiIr2O9 and Ba3BiRu2O9
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We have experimentally investigated the effects of pressure on the magnetoelastic transitions associated with the opening of spin-gaps in Ba3BiIr2O9 and Ba3BiRu2O9. For both compounds, reducing the unit cell volume by either external physical and internal chemical pressure was found to reduce the temperature T* of the transition and, to a lesser extent, the magnitude of the associated negative thermal volume expansion. The results yield the latent heat associated with the transitions, −3.34(3) × 102 J mol−1 for Ba3BiIr2O9 and −7.1(5) × 102 J mol−1 for Ba3BiRu2O9. The transition in Ba3BiRu2O9 is significantly more robust than in Ba3BiIr2O9, requiring an order of magnitude higher pressures to achieve the same reduction in T*. The differing responses of the two compounds points to differences between the 4d and 5d metals and hence to the importance of spin-orbit coupling, which is expected to be much stronger in the Ir compound. © 2014, IOP Publishing Ltd.
Pressure range mega pa 10-100, Neutron diffraction, Spin, Magnetic fields, Chemical properties, Metals
Huang, Z., Avdeev, M., Kennedy, B. J., Knight, K. S., Zhou, Q., & Ling, C. D. (2014). Tuning the giant magnetoelastic transition in Ba3BiIr2O9 and Ba3BiRu2O9. Journal of Physics: Condensed Matter, 26(27), 276003. doi:10.1088/0953-8984/26/27/276003