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The magnetic field and pressure dependence of the magnetic ordering transition in NaxCoO2 (0.6<x<0.72)

J. Wooldridge·D. McK. Paul·G. Balakrishnan·M. R. Lees
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Abstract

We have measured the magnetic field (H<90 kOe) and pressure (P<10 kbar) dependence of the magnetic ordering temperature, Tmag, in single crystal samples of NaxCoO2 for a range of Na concentrations (0.60<x<0.72). We show that in zero field, Tmag remains constant with decreasing x before magnetic order disappears at x=0.65. Heat capacity and magnetization data show that for x=0.70, Tmag is unchanged in an applied field. In contrast, magnetization data collected under hydrostatic pressure show that Tmag increases from 22.0 K at 1 bar to 25.4 K at 10 kbar. This rise is at odds with the behaviour expected for model spin density wave systems.

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J. Wooldridge, D. McK. Paul, G. Balakrishnan, M. R. Lees. 2006-04-27. The magnetic field and pressure dependence of the magnetic ordering transition in NaxCoO2 (0.6<x<0.72). https://doi.org/10.1088/0953-8984%2F18%2F19%2F024

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