Spin-glass-like H-T phase diagram for the frustrated insulator CsNiFeF6

The authors present DC magnetisation measurements for CsNiFeF 6 , which is a non-dilute random frustrated compound. They found that the maximum of the field-cooled curves occurs at T M (h) given by h= 4 / 5 1/2 (1-T M (h)/T M (0)) 3/2 , where h=g mu B S eff /3k B T M (0)(1-J 0 ), with J 0 =0.7 (the mean value of the magnetic interaction distribution), the value of S eff being determined from the slope of the H/M against T curve above T M (0). The difference between the field-cooled and zero-field-cooled curves makes possible the determination of two temperatures: (i) T R1 (h), below which the irreversibilities appear (T R1 (h)>T M (h) for the lowest values of h); and (ii) T R2 (h), below which the irreversibilities increase rapidly (T R2 (h)