NUCLEAR MAGNETIC-ORDERING IN SILVER AND RHODIUM AT POSITIVE AND NEGATIVE PICOKELVIN TEMPERATURES

In silver, Ruderman-Kittel exchange interaction leads to nuclear antif erromagnetic ordering at 0 < T < 560 pK. At -1.9 nK < T < -0, the orde red state is ferromagnetic. In rhodium, spontaneous spin order has not been reached but a tendency to antiferromagnetism has been detected i n susceptibility measurements down to 280 pK and up to -750 pK; these values represent the lowest and 'highest' temperatures ever produced a nd measured.