The low-temperature heat capacity of (Pu0.1La0.9)PO4

The low-temperature heat capacity of (Pu0.1La0.9)PO4 has been measured from T=(3 to 300)K. An anomaly was observed at T=4.1K. This transition is probably due to antiferromagnetic ordering of the Pu3+ moments, also suggested by SQUID magnetisation measurements. A comparative measurement was made for (Gd0.1La0.9)PO4, to investigate the effect of dilution on the antiferromagnetic transition in GdPO4, which showed that in this compound the ordering is still present at this concentration also.